Bryan wrote:

If I wanted to carry 2 50 foot sections of line for tieing to the tree
insted of the single 100 foot section I might occasionally need to tie the 2
sections together to reach the tree. Is a sheet bend a good knot for
holding the 2 sections together all night, again with the stress of gentle
tugging? Or should I attach the 2 sections to each other using bowline
knots?

A 'Double Fisherman' is the knot to use for this:
http://www.une.edu.au/unemc/dbfish.htm
A sheet bend is fine on a line that is under constant tension, but I
wouldn't trust it on a line that is repeatedly slackening and
tensioning. Using two bowlines will create wear points on your ropes
which will lead to premature failure.