I have a '85 Trek 870 that I put 700c wheels and 700x35 tires on. To make the brakes work I put a Peugeot cross bike front fork on and V brake, on the rear I made extenders so the pads would hit the rims and a V brake.
I also swapped out the friction shifters for Rapid Fire 7 speeds, with brake levers. I left the gearing stock.
It makes a great foul weather ride with Planet Bike fenders.
I would say, go for it!