The Entangling terrain states:

Entangling Entangling terrain is ground that seriously hampers the mobility of anyone within it.

Effects: While within Entangling terrain, a character increases the TN of all their checks to move and for Movement actions by 2.

Examples: Sucking mud, brier patches, deep snow, icy ground, moving water.

1. When does a character roll to make a check? Every time they move? Does this include the free range band move during skirmishes? Or is this specifically with regard to the Maneuver (Movement) action?

2. The Immobilized condition states it ends when, "At the end of their turn, if the character did not perform a Movement action this turn, they remove the Immobilized" The skirmish rules state, "Once during their turn...a character may move 1 range band. Note that moving this way is not an action." So a character can move this range band and still remove the immobilized condition? Doesn't seem like you're very immobilized...perhaps the language should be changed to "This does not count towards their action this turn."

On 2, Immobilised does specify that the character cannot “otherwise reposition” themselves, so that includes the “free” range band. No move at all; and at the end of the turn, they can shake it off.

On 1, I think the free range band move is unaffected; but the +2 TN applies to any action with the Movement tag. Maneuver is just one of them.

The +2 to TNs applies to any and all checks for movement. If an action involving moving doesn't have an associated check it doesn't get one due to entangling terrain, it stays check-free.

Concur with both Franwax and Nameless ronin. Note that the movement action is an additional 1 (no roll) or (rolled) 1+BS/2 bands, so even difficult terrain can get 2 bands. See p. 264, Maneuver action and Summary of a Skirmish Turn sidebar.

But also note: many talent-actions are movement type; those all take it as well, such as Fowing Water Strike (p 175, Attack & Movement) Heartpiercing Strike (p176 Attack & Movement).

As yet, I've seen no terrain inherently requiring a roll to move through.