> Preferred rim type? Special trailer tires?
I am not sure about rim types except make sure they have same lug opening
to match you wheels and are heavy duty enough for a trailer Anyone
selling wheels can give you good recommendation on rims..

Tires can be a bit of a problem. The current tire used on Airstream
travel trailers is P225 75R15 ST, Goodyear Marathon Radial. These tires
also come in a 214 and 205 size. The problem is to get a tire wheel
match that will fit into your trailer wheel wells with enough clearance
at sides and top to permit easy removal when jacking up trailer in case
of flat. Originally your rig probably had a 700-15 bias ply, 6 or 8 ply
tire. These were typically light truck (LT) tires. Todays trailer tires
are special trailer tires (ST) and have a special straight ahead tred
design, extra strength side walls, and special UV material in tire to
retard deterioration from sun. The are rated as D or E class load tires .
The ST tire will typically outlast any other tire on an RV. However, the
700-15 tires are still available and many still use them. They are less
pricey then the ST Radials.

There are other brands beside Goodyear available.

There are various opinions about radial tires on RV but radials seem to
be preferred on new equipment. You should get some more knowledable
responses from some of the other '60's model owners.

Roy