Pom Pax,
The Lincoln was really replaced as a stop gap by the Washington (B50). In those days it was probably unlikely that there were any nukes.
If possible you should read Plan Dropshot or Operation WW3 edited by Anthony Cave-Brown.
This was the US COS War Plans circa 1947 for war in 1957 and included plans for pre-emption. Cells of B29 (B50) would penetrate the USSR with perhaps 3 bombers, 3 ECM and 3 decoys.
Most interestingly was an estimate of what her allies could provide. Given that there was supposedly no cooperation between the British Labour Government and the US or indeed for some years later I was surprised that they assumed one and a half recce wings in Malta, 3 or 4 medium bomber wings in Cyprus, 2 bomber wings in Singapore. Later, apart from their being sqns rather than wings, this exactly mirrored our deployments. Malta had 13/39 sqns with part of one assigned to CENTO. Cyprus to CENTO and Singapore to SEATO complete with two purpose built medium bomber facilities.
I wonder whether there was secret cooperation at a sub-governmental level with the UK COS implementing secret infrastructure project to a US master plan.
Now that would be grist for the conspiracy theorists.
The subject of escape maps is a subject of its own.