Motorhome door is stuck

Not enough info to answer. Stuck/broken how?

Do be aware there is a recall on one particular lock widely used on RVs that can permanently lock if the key is pulled out after locking if the key blade is horizontal instead of vertical. If THAT is the problem it requires a locksmith to drill out and is probably beyond DIY repairs. But if that is not your issue, all bets are off.

RV door locks don't have to be much of a lock/latch if the RV is a Trailer. If it's a MoHo, then it can be occupied in motion and higher standards called FMVSS apply. If it's an FMVSS lock, harder to remove when it won't unlock, than one in a Trailer.

A brand called Trimark had a lot of failures. If you'll search, you may find a way to get the old out and replace with new. If you can't find a clear way to proceed and get the broken one out without damaging the door/door area, better to hire a professional. $100 to remove a $100 lock is better than $1000 to fix a buggered up door.

A mobile RV tech can probably help, too. Otherwise, when I need a locksmith, I try to drive to their shop (if any still have one!) and avoid the "service call" fee.

Can you post a picture of this Lock?

If it turns out not to be a DIY job, I would go with either a mobile RV tech, or a locksmith.

Part of the problem is, in most cases is when the outer door won't open, the screws that hold the lock set together are blocked by the screen door. Screen only, maybe even the screen door frame.

Sometimes my screen door wont let go, which makes it "appear" I cant open the door till I manually unlatch the screen door jam.

Trimark latches use a cheap metal for the striker bolt, and the high stress point on that bolt is also the weakest spot.. Nice design.

I had to "Pick" the lock (I actually used a "Pidk" designed for use removing the rear main seal on an Engine)

I was able to sneak it in and depress the bolt.. Then open the door.

Took it apart (Careful or the spring) and had a metalsmith carve me on out or STEEL. forget if it was 20 or 25 bucks (Beats over 100 for a new latch assembly)

You have a way in from the rear door
Nothing has to be drilled
You can take it apart from the inside
If you can't reset it aka fix it
Order a replacement and put the old one back until the new one arrives
You are in a good situation you have two doors
These things are relatively simple, not rocket science

Thanks for the input. I had a RV repair guy come look at it and the latch was broken so he replaced it.