Regarding TU114 the following information can be found from the interweb:
"It has an external length of 54.1 meters, an external height of 8.2 meters, and a fuselage diameter of 3.3 meters. The tail height is 15.44 meters and the wheelbase is 21.3 meters. It has a wingspan of 51.1 meters and a wing area of 311.4 square meters. The aircraft has an empty weight of 91,000 kg, a gross weight of 164,000 kg, a maximum takeoff weight of 171,000 kg, and a fuel tank capacity of 19,280 US gal."
"It produces a maximum takeoff thrust of 14,795 hp each and drives eight-bladed AV-60N contra-rotating reversible pitch propellers with a diameter of 5.6 meters."
So, fuselage 3,3m and external height 8,2m doesn't give the exact door sill height, but one could estimate the door sill being somewhere around 6,0m height, based on pictures of the AC and the 1L location.