Welcome to the forum! Lot's of helpful, knowledgeable folks here. Hopefully some others with more experience than me will chime in, but here's my opinion. I think you'd be at or over the limits of most 1/2 ton TV's with that Flagstaff. If equipped with a max towing package, you could probably pull the weight, but I think you'd be at or over the cargo capacity and the GVWR once you factored in passengers, other cargo and the pin weight. You wouldn't have much if any safety margin on those weight limits. Best thing to do is use the towing calculator linked in the "Towing Calculator" sticky thread at the top of this forum. That'll tell you how much you can safely tow based on the vehicle specs you punch in there. You can find those specs from the TV manufacturer's website.
As for the Montana, my opinion is you'd want to go one ton - F-350, Ram 3500, Silverado 3500HD, etc. That Montana (if I'm looking at the right one) has a GVW of about 15,900 and a dry pin weight of 2360.