I'm guessing it has 16½ inch rims on it, this will be the biggest issue, finding tires. Limited selection. Supposedly some Ford rims fit certain Dodge models/years. From reading (I have no direct experience) the rim issue seems that it could be easily solved if someone in the rim business could take blank (no center or lug holes) rims and machine to fit the Dodge. Dunno, just something to worry about.
A quick search shows that Firestone Transforce HT is made in 8.75R16.5LT 115/111R E and 9.5R16.5LT 121/117R E. I have Firestone Transforce on my View, don't like Firestone, but they get rather good ratings/reviews online.
Looks like a nice rig, good that it was under cover. Go over it thoroughly for damaged wiring from mice, they are most certain to have got into it at some point in time.
Replace ALL rubber components, and you will be way ahead of the game.
Hope I don't bring the wrath of moderators down on me, but there is a 670 page thread on Dodge chassis C class motorhomes on a competing RV forum group
that the OP may wish to read thru. On these old beasts, any info, from anywhere is a good thing.