Springfield: What does a copy of ToVoS go for these days? There was one offered on eBay (I think the cover color was off - but that could well be the photo and not the book itself) for $200. I don't believe it sold.
It's been pointed out here before, but there is an interesting similarity between one of the signs shown in that book and the LUE treasure map.
Additionally, I think Karl's Waybills to El Dorado is very useful. Most of the specific treasures have finally been lifted by now (along with the 25 listed in THM #6, of course) but again - read between the lines...
Good luck to all,
~The Old Bookaroo