Hey Jason, I am in the same process. I'd suggest sticking with the fork you have until you decide you will indeed need that space.
As for the gear, I would start with stuff that can be used universally on different bikes(seatbag and handlebar harness). If you can get all your stuff in those items for your trial trips just stick with that. If you pursue bigger adventures then go with a frame bag. If its not your cup of tea the seatbag and bar harness will be fairly easy to move compared to a frame specific bag.
Take a look at 12wheels stuff in the classified. He makes quality gear at a reasonable price and can get it to you quickly.
http://www.bikepacking.net/forum/index.php/topic,2427.0.html