full time solar, maybe?

Wind in the campsite could be a problem if side mounted. On the roof it wouldn’t if flat.

The issue is the batteries. You need a detailed "load analysis" to accurately determine how much battery storage you will need.

Your load analysis will differ in different geographical locations and the time of year. There is one YouTube channel where a family built a reasonably sized house (2000+ sq ft?) with all of the typical amenities (washer, dryer, dish washer, propane for cooking and hot water). They have 3 HUGE sets of solar panels. Because they live in ID, in winter they some times go 3 or more days with no real sunshine. They have a large propane generator.

https://www.amazon.com/gp/product/B07C8ZYFNV/ref=ox_sc_act_title_1?smid=A5KU5HDAPDC75&th=1

shopping Amazon i see "kits" spouting 6 pieces of 195W panels to get 1000W.
my rudimentary math tells me that 2 kits gets me 2000W.
then remeasuring the slide out tells me i could not get more than 8 panels on this rack i am dreaming up. so everything is not as i planned already.

i still would prefer to stay off the roof. being a 5th wheeler, it is npt flat. and there are other obsticles up there. things like the AC, the Fridge vent, roof vents for the cabin, TV antennae.
so the roof is not my optimal location.
i have other locations on the sidewalls than the slide. but i need to learn more about RV construction to know how/where top mount anything.
and i would think any extra awning space would be a good thing.

It can be done. It might be a fun project. Your RV is probably already 102" wide which is the maximum allowed. If you go hanging solar panels down each side it's bound to add a few inches to each side of the RV making it technically to wide to go down the highway without an over width permit.
I'm not sure how you arrived at 2000 watt with 12 panels. That's 166.66 watts per panel which is a very odd size. Modern 60 cell panels are now up to 365 watts each. You can even get 72 cell panels up to about 450 watts each. If you want to build a large system I'd at least use large panels.
If you RV is 29' long and 8.5' wide that gives you about 246 square feet. A 365 watt panel is about 18 square feet. Subtracting some for other roof equipment you could probably get at least 8 on the roof alone. That's 2,920 watts.
On a 12v system you might be able to put over 200 amps of charge into a battery bank. You would realistically want at lest a 2,000 amp/hour bank in order to accept that kind of charge and you would need at minimum 2 100A Magnum PT-100 charge controllers. I don't know of another charge controller that will handle 100 amps on a 12 volt system. Most are only about 60 amps so you would need 4 of those which adds complication.
By the way, a solar array is usually around 4 watts a square foot so those 8 panels will probably add about 580 pounds to your roof. A 2,000 AH lead acid battery bank could be make with 12 Concord PVX-9150T batteries. That would be about 1,128 pounds of batteries.
So, it is a big undertaking. I've built plenty of these, most of them larger, but mine are stationary on off grid cabins.

You mite mout them but your fear of holes in the roof isn’t realistic. Brackets sealed with Dicor, touched up every year with Heng’s work perfectly. Setup, takedown every move will get old fast electric or by hand.

A solar store in Yuma had a picture of a MH with 2 rows of panels on the roof mounted above the ACs. For 60 cell panels and 2 rows with 5 per row you have 27'x3' per row.

perhaps the best solution.

Even 2000W is one very large RV setup. I've seen a few at Quartzsite. They were on a large solar rack near the RV.

Reality: 2900W/120V = 24A AC, with losses that about 264A DC. You'll need lots of batteries and controllers or off grid controller setup. That's one hugh solar system for an RV.

It doesn't end there. There are controller and wiring losses and you only get the rated panel output at high noon, clear sky, panels aimed directly at the sun. Let's assume you get 70%: So 264/70% = 377A*14.4V charging = 5430W. So with 300W panels you'll need 18 very large 60 cell panels.

So just run your gen.

Why do you want to drill into the side and not the roof. There are already hundreds of holes in the roof in mfg. What's a few more? :h

Are we all having fun? :B :B :B

2900 watts of solar is not the same as a 2900 watt generator. You will need batteries (and an inverter) to replace the generator, then the solar will charge the batteries.

Hanging solar on the walls is a good idea but if you hang them on the slide outs how are you going to run the wires?

I have lots of screw holes in my roof for solar plus PVC conduit for the 8 gauge wire and not a single leak. All sealed with Dicor.