Here is how the drill works....having been through this about three times. They will make you an offer. You must be aware that the trees are worth something. With such a small parcel of land they are going to take, they may be the most valuable thing your selling.
Once the State has made the offer, you can accept it or reject it. If you reject it, you will end up going to court. That does not stop the State from taking your land. A little thing called "Right of eminent domain." Generally you can count if you do not accept their offer, that you will probably go right up to the day of the court hearing, and the State will settle with you. Very rarely have I ever seen where there was a full fledged court hearing on the value.
Just remember, The State is not your friend!!! Make sure if you take their initial offer that you have spelled out the exits you want onto your property. Once, in my case, I got the money plus I got an additional paved exit onto my property.
You probably all ready have a value in your mind. If you are in a rural residential area that puts the value quite a bit higher than an agricultural area. Don't count on spending the money tomorrow, but if you are patient you will be okay.
Oh yes, something VERY VERY important. Find out where your property boundaries are FOR SURE LOCATED!!! Then correlate that to the property tax description. You may be paying property taxes on highway right of way. In other words.....make sure that the old highway is NOT an easement and you are not paying property taxes on that ground.