to get into the NTRA/DRF one, you need to qualify to get there. you cannot just buy-into it. Normally, you have to place in the top 3 in another contest or series of contests.
HPWS at Orleans, I think you can buy-in for $1000 if you don't qualify for it thru another contest.
don't know about the laptops out there (I'd assume you can have one with you, in your hotel room, but not in the sportsbook nor any other part of the casino).
I've been trying for the last few years to qualify through the free online qualifiers. Made it to the finals of them a few times and been close, but haven't been top 3 in the final yet. Brisnet runs a couple qualifiers for them online where you have to be top 50 in one of their first round qualifiers to get to the final. Sept 20th is the next one.
http://www.brisnet.com/cgi-bin/challenge.cgi