Modular benchwork is the ticket, if you're expecting to have to move, at some future time. Modular does, however, add the restriction to the plan, that you have to keep the module boundries clear of things like turnouts. (not an absolute restriction, but you would have to carefully figure out where and how you'd operate a turnout that crosses the module boundary). Bridging a mod boundary could be as simple as using a bridge!
There are no "Have to" absolutes in planning, but there are some very strong recommendations, like using the largest possible radius, and minimum possible grades, and keeping everything "reachable".
Pete