I find the Hunt Planner on IF&G's site to be highly inaccurate. We really don't have a great land-ownership map system online, to my knowledge. I usually have to piece things together between various maps. It's a pain, and I wish we had something online that would make life easier. I end up using county assessor GIS online interactive maps a lot (which not all counties have online), together with Forest Service or BLM maps that show land ownership.
Unless I'm missing something out there on the WWW, I think the best bet is to get one of those mapping companies who market land ownership maps to hunters for GPS.