I think it's a good deal if the frame and wheels are in good shape with no or little rust. Hope the cotter pins remove easily (need to use new cotter pins but any LBS should have those in stock) so you can service the BB and cleanup/polish out the cranks and chainwheels/rings. Same with the quill (headset) and freewheel (rear bearings). The rest should be ok and easily taken apart and serviced/greased/oiled.

The rim strips should be replaced, most likely rubber in there and probably the spoke nipples have worn through the rubber by now. In the old days, many used Velox AND rubber rim strips (both) to keep everything in place/protected since everything is exposed in a single wall steel rim plus reducing the possibility of the tube blowing up. But true and tension the wheels first or rebuild them with new spokes before installing the rim strips. Could consider going to 700C if your brakes have enough adjustment (about 4mm) for the smaller wheel or buy aluminum alloy Sun CR-18 rims for better braking and it's triple box construction and hooked rims (about $26 each). Hooked rims will allow you to go more than 65psi in your tires.

Vintage bikes are fun to restore and ride. Upgrading is also relatively easy and inexpensive if you research and decide what really needs to be replaced or upgraded. A good LBS can order parts for you or might have some NOS items in the back and online ordering can get you the parts that are hard to get/find. Wal*Mart brake and deraileur cables and housing is only $5 and they also carry the 27" tubes too. Tires will probably be the biggest expense item if the rest of the bike is in good shape.