A2.51. No, they may move normally on the offboard map, so as to enter the mapboard on a hex which is not adjacent to the one they setup in, provided they were not scheduled to enter via specified hex which is not blocked.
A2.5. If entry hex for reinforcements is blocked by Blaze/Rubble or enemy units, entry must be made in non-obstructed hex within four hexes of the scheduled entry point but one Game Turn later. If all hexes are still obstructed, the radius of permissible entry is extended another four hexes in both directions at cost of another…
13.6b. The reinforcements can be placed in the nearest unblocked map-edge hex.
12.5f. No, they don’t.