Yes, all three garage circuits are fed separately from the main service panel. One breaker per circuit.
As others have pointed out, that's NFG. and probably would never have been permitted even back when it was first installed (I'm betting they were D-I-Y installs, with no inspections, etc.).
One of your larger potential problems now is, will you be forced to re-do it (to current code) in the course of replacing your main service panel? Or will they consider it "grandfathered" and let you slide on it at least until you actually do the garage remodel? If the latter, and
IF you are serious about doing that garage remodel in the not-too-distant future (say, several months or so), then my current suggestion would be to let sleeping dogs lie, if you can. As already discussed, whatever you put in now in the way of a stop-gap sub-panel/feeder arrangement for the existing building(s) will surely be at least partially obsoleted by the new garage build anyway. And from your various subsequent comments, it seems clear that even a stop-gap interim installation will likely be sufficiently "involved" that you'd really not want to throw all that away six months later. So if you can simply side-step that whole mess by being extra patient about upgrading the garage electrical, your life becomes much easier overall.
[Side note: It just
might help convince the AHJ to let you leave well enough alone if you were to (permanently) remove the electrical feed to the shed, especially if (as I think I understand) it is piggy-backed/daisy-chained off one of those circuits feeding the garage (and/or is in general as far into "hack work" territory as I suspect it might be). Losing one lightbulb for awhile seems an easy trade-off for not having to do a major chunk of this job twice.]
While I haven't checked the entire are behind the garage. Most of what I have run into is solid rock beneath the ivy

So I'm not sure if digging anything behind the garage is even feasible.
Well, that's something you need to get a handle on, before you can realistically assess the feasibility of each possible approach.
I mentioned the propane tanks because of the gas line underground. I'm not sure of what type of spacing is required around those with regards to electric. They actually are going to get shuffled a bit for the garage project. I know the propane company wants 10 feet from outside facing electric plugs.
OK. But in that case, they are still irrelevant until and unless you do attempt to run an underground feeder -- which I really can't see being worthwhile until you actually do the garage rebuild.
It is ivy running over mostly solid rock. To extend that backside wall is going to require a bit of rock busting work
This is one more reason I think you need to focus more on the permanent solution, and less on the stop-gap measures.
By convenient I actually meant ease of access. My car barely squeaks in the garage so having it buried by the car does concern me a bit. I have maybe 1 foot in front of the car and maybe 6" behind it
In which case, I have to question the proposed size of the new garage, as shown in that little sketch you posted. If you're THAT tight in terms of front-to-back space now, merely widening the garage isn't going to help much. Making it deeper, however....
Hopefully the attached picture will help this time. I've drawn in the rocky hill behind the garage as well as identified east and south. The east edge is the property line so I'm not able to do much there.
But unless there is still more you have not (yet) told us, there's no reason you can't move the front ("North") wall closer to the street, right?
I forgot to identify the gap between garage and shed but it is 2 foot

Also missing is the gap between shed and breaker box... it is close to 15 feet.
In which case, and given the stated difficulty in digging behind the garage,
IF you insist on (or are forced to) upgrade the wiring to the existing garage immediately, that gap might be a better place for that (temporary) support pole for the feed line. If I understand your sketch correctly, the slab upon which the shed currently sits does not extend all the way back to the garage's rear wall. That might let you get far enough away from that rock "cliff" to make the digging easier. Obviously, it would have to come out again when you actually do the garage remodel; but so be it, if this is your only way to keep power going to the washer & dryer in the meantime.
I'm only trying to avoid a buried electric feeder in a conduit to the current west side of the garage because it would have to be removed shortly.
Just in case I have not been sufficiently clear thus far, I would
NOT run any "temporary" feeder underground, period (unless, of course, you are absolutely forced to by the local authorities; but I suspect that is unlikely). Why go to that extra trouble & expense for something that you will near-certainly have to abandon and/or rip out six months later?
Feed the shed with a permanent, underground circuit and sub panel, sized to match your anticipated loads after the garage is rebuilt. Feed the existing garage circuits with new wire from the new sub panel.
I might be missing something here; but I just don't see this as feasible.
First, as you later noted, by code he'd then need a second sub-panel in the existing garage (due to the "one power source per structure" issue). Yes, it could potentially be daisy-chained off the shed sub-panel; but even so, at least one of these sub-panels would be a complete write-off after the garage rebuild. Given the other work (i.e., the new main service panel, which will surely involve an inspection) being done concurrently, the chances of this NOT being demanded by the AHJ are somewhere between "slim" and "none". OTOH, if he's just disconnecting existing branch-circuit wires from the old panel, then re-connecting those same wires to the new panel, that has a MUCH better chance of being permitted.
Second, how is he to be sure that this "permanent" feeder will be in exactly the right place vis-a-vis the new garage (which apparently has not even been designed yet, at least not in any detail)? For that matter, would it even physically survive having the existing slab(s) ripped out and re-poured as part of the new garage project? (Hmmmm... PVC conduit vs. ham-handed backhoe operator-- who wins?) Granted, the slabs themselves have not yet been discussed in much detail (at least not in this thread; I've not checked other Forum sections); but based on the currently available info, it seems pretty obvious that trying to "jigsaw puzzle" filler pieces in among the existing slabs is not likely to make for a nice smooth, level floor for the new garage. Hence, I am presuming that the old concrete will be discarded en toto when the time comes. (Besides, Placerville is far enough up into the Sierra Nevada foothills that at least some semi-serious insulation under the slab -- and perhaps PEX tubing within it -- likely ought to be considered S.O.P. for any "serious" garage anyway. So that's one more reason to figure on the rip out and re-do approach, rather than trying to cobble together a Rube Goldberg-esque hodge-podge of old/new, big/small, level/tilted, higher/lower pieces.)
But, again, I would just wait till I rebuilt the garage, and do it all at that time. Esp. if that project starts this spring... not that far away.
Agreed. The best way to deal with this whole mess is to disturb as little of the old work as possible, until such time as it ALL can be done "really right". That is, presuming the AHJ will permit this.