If I am going on a long trip, I usually have my mechanics look over the
plane, change the oil (if its been more then 25 hours) and regap the
plugs.

if I recently had these things done, then I dont do anything different
since I always plan on landing every 4.5 - 5 hours for fuel.

Ben Jackson wrote:

What do you look for beyond a normal preflight when you're about to
go on a long trip? For example, if you were flying from the west
coast to Oshkosh you wouldn't want to be within 10 hours of an oil
change or a 50/100-hour inspection.

--
Ben Jackson

http://www.ben.com/