Just to add in my 2 cents, Ive been using ForeverALoad to keep the chunks I need loaded, It does require an admin wander round and add all relevant chunks to the list but on my small server this isn't an issue.
http://forums.bukkit.org/threads/admin-fix-foreveraload-v1-1-keep-your-chunks-forever-a-loaded-1-0-1-r1.28665/