Since a full set goes around 35-50. Then just the terrain might go for 25$ or so.I feel like that would be high for just the hex terrain. If we're talking about terrain plus both pieces of the ruined building (and the accompanying card) then that's probably a decent enough place to start.
The non figure, non terrain items probably aren't worth selling at all...the other bits aren't particularly valuable since most folks that want them can likely get them other places easier.
The cards without the figures would be a tough sell too...although they may have trade value to folks that lost or damaged their originals...if you or your family are into other games they may be worth more to you that way. Try trading them for stuff you might want through this site?