In the steel days, mechanics would spread the rear to accommodate. It can be done, not advisable with the current knowledge. I ride some modern & some vintage hubs. So long as they are in great shape & serviced properly, they should spin just about as well as anything new. You can pair just about any type of rim, modern or vintage to your hubs. I tend to stick with vintage hubs on vintage rims for the appeal. But not everyone cares so much about that & new rims will work just fine. New brakes should bolt up fine, as well. A good set of modern, or even vintage brakes, will help a lot. I usually swap modern pads & holders into my vintage brakes. Mostly Nuovo record & they perform just as well as my new mavic & Campagnolo record brakes. There are many ways to skin that cat of yours. Just depends on what you want to do with it in the future. I'd hate to see you get rid of it, if there are things you really like about it. I think s good steel frame often becomes a standard by which everything is judged.