New here & source for motor parts

Welcome to the joys of an older RV.
As others have mentioned, the first thing is to determine the "chassis" of the RV. The chassis is the motor vehicle portion of the RV. Chassis parts are usually very common auto parts available at most auto parts stores or online retailers.

One important fact is to make sure you know the actual year of the chassis as RV manufactures "RV" years may be a year or two past the chassis manufacture's year. It normally isn't that big deal unless (like mine) you're straddling a chassis change where the year (and month) is important as parts changed. Also if there are component differences (there were two transmission designs in my year each with slightly different parts) you need to know which you have in order to get the right parts.

As for the "coach" portion of the RV, many of the major components are standard RV parts used across many manufactures or more universal that swapping isn't that big a deal. So a A/C may be the same used across dozens of RV makes and models from that period and not specific to yours alone.

Many older RV owners do like using RockAuto simply because it allows you to focus on the parts category as well as see multiple options from cheap knock-offs to OEM parts. I avoid retailers on Ebay simply due to the abundance of counterfeit parts found repackaged into OEM boxes and sold as discounted genuine OEM parts.

I also use a national retailer (Advance, Auto-Zone, NAPA, O'Reilly) as you can take the part into the store and have them match it up if there's a question as to if you are ordering the right part. I find they usually have many parts in stock or at least a day away in a warehouse. Of course, unlike RockAuto, your selection may be down to OEM, a couple brand names, or their own branded part. However, being able to have a hands on selection option sometimes saves the day.

So, enjoy your mature RV.

I looked and it appears that yours my be on a F53 chassis. Parts should be available at any autoparts store. If they don't have a listing for the F53, have them look at the F550.
I believe you will need to drop the fuel tank to replace the fuel pump. drain the tank, and lower it using a tranny jack or motorcycle jack.

I agree with towing to your home for repair. Better working conditions, all your tools, electricity etc.

what chassis is your rig on? Make and model?
Rockauto.com, Amazon, Ebay, AutoZone, O'Reilly's are some places. Coach parts can be found at Colaw

Here is a link to RockAuto that has all sorts of stuff for a Ford F53 chassis.
here is a link to RockAuto that has all sorts of stuff for a Chevy P32 chassis.
You didn't mention chassis manufacture. Four Winds buys the chassis and adds the coach body.

Richard

if I were you, I,d have it towed to your house. this sounds like months of work. build a garage over it and play when you can.