We are a full Allstate family, but found Allstate could not touch the prices or coverage of National General Insurance (Good Sam).
Allstate even with multi-policy discounts was 75% higher than Good Sam. Also the National General policy is a 'replacement value' policy for one model year newer than our trailer in case of a total loss.
Allstate's policy would exclude 'road hazard damage' to the TT if some debris from the highway caused damage, or if a tire failed and caused damage. We know people who have had several thousand dollars damage due to a blowout.
Ask for details of the coverage, and get quotes from at least three companies.