Mostly time and legal drafting: reviewing the state contract for control language, obtaining a placement letter from the affiliate, and possibly amending contract terms. Government fees come from the USCIS fee schedule and do not change because the site is a park.
The contract review is the cost that prevents the expensive outcome
Government charges for an L-1B petition, including any premium-processing request, are set out in the USCIS fee schedule and are the same whether the transferee works at the affiliate's shop or on a state trail corridor. The offsite placement changes the preparation cost. Someone has to read the affiliate's contract with the state agency clause by clause for anything that gives the agency authority over personnel, hours or methods, and if such language exists the parties may need to negotiate an amendment before filing, which costs legal time on both sides.
The affiliate must also produce a letter describing site supervision, equipment ownership and reporting, and it may need to explain how the firm's specification will be applied on the project. Translations of the Québec firm's payroll records, training logs and the specification manual are a further line. Set these against the alternative: a petition filed without the review that draws a request for evidence during the short building season and pushes the whole assignment into the following year.