Horse being written after years

Question
"Hi - I have an almost 11 year old QH gelding that hadn't been ridden in a few years & was basically just loafing
around eating when I got him. He basically doesn't want to be ridden after living a life of leisure for so long!
I don't have a roundpen but ride him in a huge outdoor arena.  When I ask him for the trot, he trots about
2wce around the arena & then gets bossy, tries to put his head down & start bouncing around.  He pulls at the bit & constantly trys to put his head down really low.  He even tries to canter. I have to constantly keep a contact on the rein to gently try to pull his head up when he does this while urging him forward with my legs.  This is quite a balancing act!   He has never bucked or  anything, just hopped around, but riding him is alot of work!     
He was ridden in a Pelham bit before but I have never used it because I think it's too hard.  I have him in a D-ring snaffle.  I had a student trainer come work with me & she said his mouth felt numb & to get a twisted wire bit, but I feel that would hurt his mouth.   She also said to just
ignore him & urge him forward, that he's "all talk."  I continue asking him to just trot & the ride gets really bumpy.   I am trying to be patient with him & not get frustrated.  If the trainer rides him he will be a perfect angel.  He only acts up when I (his "mom") am on him.
What do you suggest?  

Answer
Hello Sharon,
Let's think of what you can do on the ground to show your guy what you want him to do. What kind of ground work do you do now? A great thing to learn to do is to send him around you in a circle at the trot and stand still, will he keep going around you?-you're not turning with him- until you lean over and swing your rope towards his hind end and he turns to face you. The idea is that the horse will be as good in the saddle as we prepare him to be. Look at what happens when you lead him, does he push into your space? When you saddle him does he start flipping his head or move his feet? If he truly respected you as the leader of your herd of two he would not be telling you "No" to so many things. Now is the time to focus on every little thing that happens from the time you bring him out of the stall so that he thinks you are definitely the kind of leader he has been looking for. Let me know what kind of things happen on the ground or at the walk before you trot when you are riding and I will try to come up with a recipe for you. I think it is great that you realize that you need help in your relationship and not a stronger bit to MAKE him do it, you're really going to enjoy learning to clearly communicate your idea to him and ALLOW him to follow your suggestion.
Talk with you soon,
Caitlin Day Huntress