Wow long time! Are you looking for a mag style wheel to go tubeless? Or sticking with spokes?
If you go to a totally different wheel, the front will be a bit troublesome but the rear will be the hard part.
First, you need to stay with the stock axle, yet you need to get bearings to fit. So you will need the I.D of the current bearings on your 73. Then you need to find out what the O.D of the bearings for the new wheel are. From there, you should be able to find something to fit but it might be pricy if it is an odd size.
This is for front and back. You will most likely need spacers too for centering the front and getting the correct offset for the rear so the chain is straight and yet the tire is in line with the front or at least close.
If you just need rims, maybe try buchanan spokes, they sell rims too for a decent price for the quality.
The ride IS the adventure. The destination is just to get gas!