With an 8500lbs tow rating I’m going to assume that you have a 1/2 ton truck? The Cougar you list is way too much trailer. At 7400lbs dry weight you will be well over 8500lbs loaded to start. Keep in mind the tow rating of newer vehicles is calculated assuming 150lbs each for a driver and 1 passenger. Any other weight added to the vehicle reduces your rating pound for pound.
The tow rating is not the only number you need to be concerned about. You also need to consider the vehicle payload and axle ratings. The payload must be enough to support the trailer tongue weight and weight of all passengers and stuff in the vehicle. Trailers should have at least 12% of the loaded weight on the tongue to be stable for towing. That’s at least 1k right there.
I suggest you do more research and as a newbie learn about towing, ratings, wd hitches etc before jumping in to anything. This forum is a good starting place. You’ll probably find yourself limited to trailers under 6k dry weight. Don’t forget that your kids aren’t going to get any smaller.
To give you an idea, we have a similar sized trailer that weights 1k less (empty)than what you are looking at. Lightly loaded we were 7600lbs which is just about the empty weight of that Cougar. We towed it the first year with a 1/2 ton truck. It pulled it ok, plenty of power, but we were always 400lbs+ over payload, right at the rear axle rating and hitch rating. We added airbags and load range E tires to help and used a $3k Hensley hitch. Not the most enjoyable experience. We now use a 3/4 ton diesel Ram in complete comfort.
Consider the length as well. At 34’ you will be limited in site selection and won’t be able to fit in a lot of places. Gas stations etc can be a challenge too. That is a long trailer for a newbie with little or no tow experience. If I were to buy again I would keep it under 28’.
'17 Ram 2500 Crewcab Laramie CTD
'13 Keystone Bullet Premier 310BHPR
Hitched by Hensley