Their realistic options become the MVC (Dallas Baptist is an affiliare in baseball so having a full member in Texas can be a good thing), Horizon and Summit. There are other alternatives in theory but in practice, each won't work.
The MWC? no football, no membership.
The WAC? too far flung and too academically inferior for Rice's brass to accept. They won't be too thrilled with Dixie State, Utah Valley, Tarleton State or GCU.
The Big West? Rice's academics match up perfectly and olympic sports might become more competitive but even with a sweet travel subsidy, they'd be literally stranded on an island. Hawaii won't be thrilled flying to California and then Texas and then back to Honolulu, plus who do you pair Rice with, UC Riverside?
The WCC? Gonzaga and Saint Mary's won't take kindly to Rice's hoops tradition and Gonzaga calls the shots. BYU and Rice could work as travel partners I suppose, but unless there's a 12th member relatively nearby that's just stretching the footprint too far east.
The Big Sky? Wow. Nuff said