Folks:

My copy of the NEC doesn't actually restrict the voltage drop for
residential
wiring, but recommends a 3.6v drop in the branch circuit and a 5v drop
including
both branch and feeder together 'for reasonable efficiency'. Seems to
me a
circuit coming right from the panel could use the 5v value. These
are both
for 120v circuits, by the way. (3% and 5% are the values given, I
think. I don't
have the book on me right now)

Using the 3.6 v value, you can run this much 2-wire cable to your
furthest
receptacle outlet:

15A - 64 ft. of 12 AWG or 40 ft. of 14 AWG
20A - 48 ft. of 12 AWG

Unfortunately this adds up pretty quick.

Using the 5 v value:

15A - 89 ft. of 12 AWG or 55.5 ft. of 14 AWG
20A - 66.5 ft of 12 AWG

I said 'receptacle' because it's not likely that a light would draw the
full 15A, and
it's easier to predict what the current will be. I don't think too many
residential
fixtures draw 1800 W.

Cordially yours:
A.P.M.F.