For long water lines, it's better to buy slip joint pipes then glue together. The glue doesn't give and when the land around it moves, the pipes break. Slip jointed pipe can move quite a large distance and still retain it's seal.
I'm not sure how small you can go in pipe size, so that might not be an option. My house has a six inch line that my wife and I installed. I know you can get 2 inch pipe with slip joints, but don't know about any smaller sizes.
My longest run was 1,200 feet to a house I owned at the bottom of a hill. The original line was thinwall and it had more leaks in it then it was possible to find. It also had over 100 pounds of preasure at the house, but 65 pounds at the meter at the top of the hill. I dug the trench for it one day, and layed the pipe the next. Backfilling the trench was the hardest part of the job, but that's the way with most trenches.
I used schedule 40, one inch pipe in 20 foot lengths with the bell ends. If you have to glue, be sure to use the right pipe. The bell end is probably three to four times longer then any coupling, and will give you ALLOT more surface area for the glue to hold the pipes together.
Always use purple primer. It's not really a primer like paint primer, but a chemical the prepairs the PVC to let the glue work. I always use clear glue. I'm no expert on this, but I'm on really good terms with my water district and they have allot of expereince in what works and what fails. They told me that clear glue with purple primer is by far the best way to glue PVC together.
Eddie