HI, been really thinking about trying out an overlanding trip for next year. Would like to ask for advice tips, experiences, and maybe some best websites to research. My ride is a Zforce 800 trail. Looking to know of items some have felt best to bring and what not. Used to backpack with my sons and have camped many years. Thus, still have light tents, jetboil and gadgets. Will most likely stay within Idaho for trip.

Since you have experience backpacking, that is all the camping gear you would need, just toss the backpack in the cargo box.  The nice thing is you can carry extra supplies, like a cooler to hold more food, & carry more water. Extra fuel & recovery equipment would be the most important additions, if you do not already carry it.

For recovery gear, a tree saver strap, winch extension rope, a couple soft shackles & a couple winch strap recovery rings would be recommended.

A battery powered chain saw is very handy if you don't already carry one.

SPARE BELT and tools to change it.
Spare fuses.
GlueTread All-in-One Deluxe Kit Sidewall / Puncture Repair kit
Small 12 volt air compressor

If no one is riding with you, strap the backpack to the passenger seat to make room for more stuff in cargo box. The floor drain holes are large enough bungies could be used to strap a container to the floor.

Load up & roll out!
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Depending on how much you want to spend, a few luxury upgrades:

* Ozark trail tent cot (Walmart brand - currently out of stock).
* Foam pad for cot
* Small 12 volt fridge, and a power bank to keep it running. Charge the power bank with machine. On Amazon, there is a $201.00 "VEVOR 12 Volt Car Refrigerator, 37 QT" - has dual zones, freezer / refrigerator. It is bulky in size, but should still have room for other stuff in the cargo box. The 53qt fridge nearly fills the cargo box, I have one. I upgraded to the 63 qt model. 
* Razorback offroad cargo rack - Very expensive, but nearly doubles bulky stuff carry capacity.

If you are going alone with no other vehicle maybe consider taking a jump starter for extra peace of mind.  I always take mine
https://www.amazon.com/gp/product/B015TKUPIC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
But there are tons of options out there.

Very good information fellas. "Strap backpack to passenger seat" like that idea. Battery operated chainsaw, winch extension, jump-start box...etc. Have most items already in garage. Do need to get spare CV belt and maybe practice replacement once or twice. RBO does have sweet rear racks. Although, nothing fitting a 2023 as of yet. A friend said they called and are just waiting for more cfmoto owners to inquire. $1000 is a big spend though. whewy.