If you're really into primes, I would suggest either the DA70 or the DFA100. While you don't want to be hauling around a whole lot of unnecessary gear, you don't want to "limit" yourself too much, either.
To see what you can do with a short/mid tele lens and landscapes, you might want to pick up the February 2009 issue of
Popular Photography and check out the article
TELEVison : a long lens brings a new perspective to scenics (p. 24), which explains how you can use lenses 70mm or longer to shoot landscapes.
Especially if you were to go with the DA70, I don't think you'd have a problem fitting everything into a smallish fanny pack.
HTH,
Heather