I can tag along I just had to get vetted which isn't a hard process but it takes a few weeks.
You can tag alone. If you want to hunt you pay the $130 for the year (you have to pre-register any firearm you take into the base even if you are not hunting) I am pretty sure you have to go thru the background/screening check-in advance.
The base is huge. There is no "scouting" allowed, You are not allowed to hunt on Friday (unless the rules are different for Elk).
I was chasing pigs and I found them. Many of them were in "No hunting zones" hanging out with the Elk, one of them had a wounded shot but it was on another no-take zone, but we found a few pigs, little bastards make the cross into private for safety and they literally outsmarted me (they waited for me to drive by and when I parked, they run across the fence in to private..lol)
Usually, FHL does not disclose what areas will be open for the weekend until l Friday I believe. You also need to know if the area is a weapon "restricted" area or not. Onyx is not going to help you since ONX does not have the FHL zone boundaries and the FHL map is shitty. You should also consider taking a 4x4 some zones are tricky to get around, especially where pigs hide.
If I was you, I would do my homework about the zone boundaries in detail, review the number of game taken in previous seasons and where they were taken.
In essence, you need to have plan A, B and at least plan C. Getting around from one zone that produced game is not easy (time-consuming).
Is it worth paying to hunt for the year? How far is your drive? My drive is 6hrs. I hunted it once and I knew, I could not justify another trip for pig so I bought the few days pass and I am glad I did.
I would go along with your buddy, buy a couple of days hunting permit and a pig tag and bring your bow (if you have one). You could run into a pig in the same area where you are hunting elk. I am sure your friend would appreciate you not shooting a riffle for a pig where your friend is hunting Elk.