27" is NOT obsolete, your choices are smaller but there are still plenty of very good 27" tires on the market. Vittoria Zaffiro, Panaracer Pasela or the better Pasela TG, Schwalbe Marathon (finest touring tire on the market regardless of size!), Conti makes several models like the Gatorskin, Ultra Sport, Tour Ride, and Super Sport Plus, and Michelin World Tour.
Tube wise any 700c 28-32 tube will work. The only thing with those tubes is that they use a presta valve which means you have to convert your rim from Schrader to Presta which will cost you about $4 for the pair, see:
https://www.biketiresdirect.com/prod...ta-stem-savers You have to remove a section of your rim tape where the stem hole is, insert the adapter and recover the rim tape over it (or replace the rim tape with new tape if the tape is old).