Yes — a turnkey installation contractor takes the job from the graded pad to the keys, subcontracting the trades under one contract. It costs a coordination fee and saves you being the coordinator.
Short answer: Turnkey means one contract and one name responsible for the sequence: site prep, footers, transport and set, trim-out, utility hookups, skirting, steps and the inspections in between. The contractor hires the trades it does not have in house. What it usually does not include is the land itself — zoning, septic permit, well — and the dealer's part of the deal. Read the scope line by line, because 'turnkey' is a word, not a standard, and two turnkey quotes can cover different things.
Reviewed by a manufactured home setup contractor and dealer.