When the BB divisions stood in on their battleship raids during the Pacific War, their usual formation speed was 15-20 knots. The cruisers and destroyers went first to check for submarines and surface opposition, and then the BB's weighed in and destroyed the Japanese facilities.
No need to run with the carriers anymore, like they did in Adm. Willis A. "Ching" Lee's day, when the fast battleships were customarily used as glorified floating AA batteries.
Nowadays, they would typically accompany an embarked Marine Expeditionary Force anyway, so I don't see the problem.
And while we're on the subject, we might want to discuss whether any other of the old gun cruisers are still laid up. The Newport News and St. Paul did yeoman work during Vietnam, as did the Boston. Another new-class CA, the Oregon City, was laid up soon after completion and may have seen little if any service. There were also a couple of latterday CL's, the Worcester and Roanoke, which were basically 13,000-ton CLAA's armed with 12 6" guns in high-angle gun mounts. Obsolete as AA platforms as soon as the Pacific War was over, their high-angle guns could be useful in some GFS situations.
There was a move afoot in the 80's or 90's to sell the Worcester and Roanoke to one or two South American navies, but I don't know what ever came of that. Anyone know?
There might be some, but during the first Gulf War the USAF used some cruiser tubes to make bunker buster GBU's. It was a shake-n-bake engineering project that yielded a dozen or so of these special purpose bombs.