We use forms like this. https://dwr.virginia.gov/forms-download/PUBR/permission_to_hunt.pdf

You could add a Hold Harmless clause as well.

https://dwr.virginia.gov/wp-content/uploads/privatepropertypermission.pdf

A letter from my attorney advising that if my land is crossed they will be shot! 

I would not use an online form. I would seek legal help to get what is needed and necessary. 

We aren't allowed to shoot anything around here! Ask Candice.

We asked our neighbors for permission to access and they said yes. It's worked out well so far.

(So the answer is, I don't know what a good legal form is)

Wouldn't you just grant them a revocable license?
Google 'revocable license to use real property'
And you'll probably get something that works for you.

You probably could grant them a limited and revocable license. The less famiiar you are with the person the more restrictive a detailed the license should be. Candice A. Donofrio had a good suggestion, but the advice of an attorney may be necessary.

My legal skills are not up to this challenge, Fred Griffin Tallahassee Real Estate 

Fred, another thing to consider to the portion of your question dealing with giving permission to hunt on one's land is  making sure you check with your insurance company before anything else.  Some insurance companies may not want the added liability risk involved with someone else hunting on your land, or have stipulations in place against doing so.

An easement is technically a license, but does not need to be granted in perpetuity, you can assign an expiry date or grant permission for only one day, if you like. The other part is a "hold harmless" issue, to protect you from lawsuits if anything happens to the hunters; basically a waiver, but you may still be liable for "gross negligence". It's best to have a smart lawyer draft this to make sure to cover all the little angles.

Of course every state has their own set of laws for these situations.

Many places they have recreational uses statutes that protect landowners as long as the lease price is below a certain amount.

Also one provision that many landowners require in a recreational/hunting lease is that the tenant has to have insurance to protect the landowner from any liability involved with the tenant's activities.

Fred,

Perhaps Bob Crane can pipe on this question, since he manages Forest Land.  A

I'm not sure what a good legal form would be. 

Never heard of such a form... I'd probably get an attorney to draft one. Of course, I live on .15 of an acre on which a 3200+ sf house stands... so not something that would ever come across "my plate."

It might depend on the area of land on the property.  Is it fenced in?  Is it actively in use?  Or is it barren and they could drive a truck across it without causing any damage or needing a gate key?  How much of an area do they need to cross?  Is it a 5 minute walk or does it take an hour?

If it's a short walk, maybe just a gentlemen's agreement to not shoot anything while on your property in exchange for a couple venison steaks or jerky off the first kill?

Oh gosh, I'd be afraid to give stock to anything I learned online for this, Fred. There is too much liability not to reach out to a LOCAL attorney - it's an expense but, one well worth the cost, in MHO.

Good luck!