New to 5th wheel with trailer idea

I am looking for some advice and verification. I have been a camper most of my life but new to the 5th wheel camping. Loving it!! Late last year we bought a 2007 Gulf Stream Mako 28.5ft. About the same time we bought a 2000 Chevy 3/4 ton truck with 6.0 motor and 410 gears, long box, and 145K miles. The couple times we pulled with it, it pulls great! I guess I have a couple questions. I also have a polaris ranger UTV, 6 x 12 trailer it fits on, a kids dirt bike, that fits on the trailer. We also have 3 Kayaks. There won't be many time we need all the toys the same weekend, but... When we do I am wondering my best options. I am first wondering if my Mako is safe to add a hitch on. I have a buddy who is very good at welding and have the hitch already off a friends who never uses it. Where do I find what my trailer is rated for? I believe my Ranger UTV weighs about 900 lbs, trailer for ranger 1200lbs, dirt bike 200 lbs. After I find out if the trailer hitch and the Mako is ok with this, I want to make sure my truck is ok. I think it is but wanted a couple opinions. For the kayaks I have seen online a front hitch added with a goal post style rack for the kayaks up front up top. Or I was thinking about adding a rack to the UTV trailer that will be pulled behind the 5th wheel. Ok... I know that is a lot but I am hoping for some advice!!!