I've been to UNF many times with the 'crew' - in a bone stock 1991 Trooper.
YES
STOCK 'ZU's will do quite fine.
In fact, I'll say that running UNF a couple/few times is the perfect place to cut new "four-wheelin' teeth" with a great group of people to learn from.
JUMP IN AND JUST DO IT!!!!!!!!!
8)
The only 'improvements' I've done to my Trooper is to add the 15x7 ISUZU 'snowflake' rims with 32" tires. The other two-three times I ran UNF I had the stock 15x6 alloy rims with standard 235/75 tires - with no lift and managed to run the Daniel trail both ways - quite challenging, but fun 8)
Yes, there will be a couple of trails that taking the bypass will make more sense for new people, but usually in those spots, people can get out and watch the more experienced people take the harder lines.
Great Learning Opportunity :!: :!: :!:
Truthfully, the first year we (wife and I) went, by the time it was over, my steering wheel had permanent finger impressions, as did the dash on the passenger side - a couple of times I thought my wife was going to rip the overhead grip off the roof - but after all was said and done, (at least) I had a new level of respect for both what I could do and what my truck could do as well - with open diffs at that - and the friends we made will last a lifetime
Cheers,