I wouldn't worry about it at all. I have never heard of anyone having a problem with any rig having a generator in the front storage areas in regards to its weight. The only reported surprises have been what weight gains which can cause some issues with front pin weight, too much weight in the front axle or the RV, the rear axle of the TV, or things like that. Overall, I wouldn't worry about the weight of the generator in the front storage area unless you got some 12,000 watt behemoth which probably wouldn't fit anyway.
A reasonable rated capacity generator that can fit in the front cap should be supportable by the framing and sheet metal. That would be the least of the concerns (unless that area is rusted out). Again, I'm only suggesting that things are in good order. But I'd pay more attention to what it does to the weight distribution and wish that all ratings for the TV and the RV are maintained.
Let us know what generator you get...
