Considering that even on a small aircraft as the 737 a C check usually requires somewhere between 2 to 4 weeks
It really all depends. A C Check is a collection of work cards that are packaged together and done at hangar inputs. It is up to the airline how they are packaged. When BA introduced the Tristar in its shorthaul operation in 1974, they tried to complete the C checks overnight. To accomplish this the C Check was broken down into about 3 packs and done one a night. It didn't work very well and in the end a 24hr input took over.
Even out in GF in BAH we did our B732 C Checks in 3 days. The only real disadvantage of short inputs is that some jobs take longer than 8 hrs, and these have to be done in special inputs that need planning.
There are loads of ways of planning aircraft checks. On a new aircraft, with no corrosion problems, there is no reason that overnight inputs will not work for the first few years.