Aloha Stinger,
NAPA carries a brushable seam sealer made by Martin Senuor in a quart can, on-line price is about $32.
Part Number: MS 4200
Designed To Eliminate Air, Dirt, & Water Between Body Panels
Paint Product Application : Brushable
Paint Product Color : Gray
Paintable Type : Yes
Probably other large auto parts chain will have something similar.