As a minimalist by nature, I wanted to address the bivy issue. Personally, I much prefer bivy sacks over tents while hiking. I typically hike with a bivy (packs to the size of a 2-liter bottle), and a silk liner (coke-can). when weather is questionably cooler, I'll bring along a wool blanket (packs much smaller than a sleepingbag). This setup is much lighter and compact than a tent and bag.

HOWEVER, the downside to bivies is lack of 'living' room. No reading. No writing. No travel-chess or cards with traveling partners or new friends. No place to change in the rain. No place to stow your gear. Bringing a military poncho which unsnaps flat, suspended over the bivy can help provide a little extra living room.

Anyway, as long as youre on a bike (which will carry the extra weight) I'd suggest a small one-person tent over a bivy