You have three options when it comes to your wheels,
1) Locate a set of used wheels, junk yards, swap meets. You may want to see if there is a MOPAR club in your area.
2) Check magazines like MOPAR Action and MOPAR Muscle (or their web site) there are several supplier of wheels for 60-70 MOPARs
3) If you’re planning to go with modern wheels and tire combination, you may want to consider a disc brake conversion kit.
Wheelvintiques.com
Stocktonwheel.com
Specialtywheel.com
Cokertire.com
As for the "adapters" they are great, if you don't plan on driving the car, I think in the long run you'll enjoy driving more if you don't have to worry the adapter failing. Back in the 60s you did have the option of a conversion kit, but it's the way to go if you're building a driver.