My old Steve Bauer is in need of a front wheel (hub is shot) and rear wheel (replacement rim likes to go out of true and spoke tension is inconsistent).

The bike is from 1987 and originally came with a six-speed freewheel, SIS, and cone-and-cup bearings. Currently it has a seven-speed freewheel, which the (second?) replacement SIS downtube shifter handles pretty well.

Should I go with a vintage wheelset, with threading for a freewheel, and cone-and-cup bearings? Or should I switch to a newfangled freehub, which I assume is likely to come with sealed (?) or cartridge bearings?

The cost difference is probably not that great, looking at used wheelsets.

I understand that the rear axle length might or will be longer, and the frame would have to be spread a bit. A local bike shop says they have the jig to do this.

The bicycle is typically used for commuting over often poorly-patched pavement. The seven-speed 13-28 freewheel serves me well. I don't see a big need for extra gears. I want to keep a downtube shifter. I would be willing to replace the shifter and its entire stack of shims and washers and whatever, because I am sure that some shims and washers are missing already. I don't know if an 8-speed downtube shifter and all its associated hardware is available at a reasonable price.

Any advice is appreciated.

Thanks
Ed