The B-29 wasn't strategic in terms of Cold War capability against the USSR, in fact SAC had downgraded it to 'medium bomber' in classification.
SAC did modify a few dozen with inflight refueling as the B-29MR but that required stripping off nearly all defensive armament and giving over half of the bomb capacity to fuel tanks. And even then the missions would be one-way:
http://b-29.org/charlie/charlie1.html
The developed B-50 was semi-strategic and had inflight refuelling capability from the outset.
SAC did modify a few dozen with inflight refueling as the B-29MR but that required stripping off nearly all defensive armament and giving over half of the bomb capacity to fuel tanks. And even then the missions would be one-way: http://b-29.org/charlie/charlie1.html
The developed B-50 was semi-strategic and had inflight refuelling capability from the outset.