Judging by recent US foreign relations, the Philippines, Thailand, Indonesia, and to a certain extent Malaysia have already signalled they won't be allowing the US to use their sovereign territory as staging areas to counter China. I'm not sure smaller countries in the area would have the appetite to host US military when they're in the backdoor of China. So looking at what's left of INDOPACOM assets, B-1s are limited to launching from Kadena AB in Okinawa and Guam.... And that's with tanker support as well to increase their combat range.SCS sea is big, and B1B is fast China may not able to intercept that plane fast enough. Most of times it would be Chinese surface ships encountering US forces first and foremost. Would a 052D spot a B1B first or B1B spot the ship first? I think this is important.
Utilizing Chinese satellite reconnaissance and radar coverage, the US would essentially be telegraphing when and where their bombers (or airborne assets for that fact) will be coming. That gives ample time for the PLAAF to scramble J-20s to shoot them down BVR stealth style, especially with support from AWACS and ground radar. B-1s might be fast for a destroyer to hit, but let's see it go up against our fighters. Even if we don't hit their bombers, their tankers are sitting ducks with limited countermeasures. So unless these B-1 bombers intend on making it a one-way trip and use kamakaze attacks to take out our Southern Fleet, I'm not sure if that strategy of using B-1 bombers is all that sound.