Inquire from dealer 2 if they will do warranty work from an RV purchased from dealer 1.
This much I know, if you take "second best" you'll always regret it, knowing if have the chance to get 1st choice, even if it means waiting a while.
If you settle for 2nd, you'll always be nit-picking it and saying, "I wish this camper had that feature that the other one had!" It may be little, but over a short time, it will become a bigger and bigger irritation.
There's nothing wrong with waiting. You have an advantage if you wait the 20 week. 20 weeks is 4 months. Take the amount you'd be making on a loan payment over the next 4 months and tuck it away now. Then when the camper comes in, you can either apply it to the total cost, bringing down the amount you may end up financing, or use it to pay for tags, title, and insurance for the first year when you do get it.
If you wait, and tuck that money away, you win both ways! Get what you want and save up a bit of capital to use when you get the camper.
Edit:
I somewhat disagree with SoundGuy. At least in Indiana, we've never had any heartburn service from our local RV dealerships. Now granted, for actual warranty work, I always taken my campers back to the place of purchase. But once the warranty was over, I never had problems getting service from other dealership-service shops.
We purchased our first TT, a Dutchmen from Tom Raper RV, which is now Camping World in Richmond, Indiana. Stouts RV (also later became a Camping World) (south of Indianapolis), serviced it, as did Modern Trailer RV in Anderson, Indiana.
Later we purchased our Keystone Springdale from Stouts RV, when it was still Stouts, and not Camping World yet, but then Camping World assumed new ownership and Camping World continued to honor the warranty with no quibbles what-so-ever. We also contacted Mount Comfort RV (East of Indianapolis) for servicing our Springdale, and they told me to bring in on. But we ended up using Modern Trailer RV in Anderson, Indiana for on-going service repairs since we eventually moved closest to that facility.
We purchased our Keystone Outback from Walnut Ridge RV (New Castle, Indiana, and they took care of my first year warranty work, but the folks at Modern Trailer (Anderson, IN) said they would, but we decided for the first year to go ahead and use Walnut Ridge. The Outback is now long out of warranty, Modern Trailer is providing me with everything I need for my Outback. Modern Trailer does not sell the Outback model, but the do sell other Keystone Models. Walnut Ridge sells Outback, but there are some models they don't stock either. Mount Comfort is available and have no problems with servicing any of my camper, even though I've ever purchased from the.
What I'm saying is, you are best to check with each individual dealership-service shop to find out their willingness for your individual repair.
I do know, a good business will not turn "business" away. Working with all of my dealership-service shops, they have all been partial and fair and truly worked hard to fix my issues. In all cases, even warranty word, my name went on the "list" and I was serviced in order, first in - first out, no partiality to where the camper was purchased.
A good dealership will welcome repairs from a customer who did not purchase an RV from them, because they know if service is good and open to all, they just MIGHT get the next purchase!
It's kind of like the dealership we went to when we purchased our original Pop-Up. The salesmen told us they LOVE to sell pop-ups, even though they had the mega Motor Homes too. He said, (and I never forgot), sell "them" a pop-up today, and 3 years from now, they'll come back for a travel trailer if they are treated fairly! Same is true for repair shops!
I've nothing but good experiences with RV repair shops. Maybe it's my location, because RV dealerships are in competition a bit more in Indiana, where the competition is a bit steeper. But I can't see any business turning folks away!