To confirm Roadguy's suspicion and to further clarify my thoughts on the above, i didn't suggest a bidding strategy as i didn't think it would be successful in the zones that could be bid... and lots of caveats as to zones that can't be bid given the parameters laid out by the OP and would have wanted to clarify first if the PRICELINE EXPRESS offer suggest was not acceptable...
Central East could be bid but if successful likely land The Cromwell which would want to see if this was an acceptable property
Central West hotels are much higher priced than bidding limit above
Strip Northeast, Strip Northwest, Strip Southeast, Strip Southwest all have hotels that could be won that would put the OP outside of the required 'between MGM and Treasure Island'
For $75/nite i thought the likely landing of the Mirage was a very good deal, worth the $10 more than NYNY, and ensured getting something within the designated parameters... for the sake of time i was suggesting this first before listing all the issues when bidding the other zones (but you raised the point, and i had a little more time today than when i gave my previous reply, so i figured i'd address it now)
Please remember to return to BetterBidding and use the PRICELINE and HOTWIRE links on the board to begin your travel purchases... or thru our sister site MAPSandHOTELS.com for your regular rate purchases.