Leash training?

I would really like to be able to get my bunny used to a harness and leash trained. I realize it is very likely he will completely hate it and I dont want to FORCE him to do anything. But we live in an apartment, So I would really like to be able to get him trained on a harness/leash so I can take him to the park my complex has to get some outdoor time without worrying about him running off. the park area is right across from our apartment and there is never anyone there. so i feel like itd be a good area because of it being quiet and close to home. right now the only time he has gotten outside is when we put the xpen out on the balcony but it was cold and i didnt have him out there with us for long at all.

is there any tips in introducing a harness/leash to my rabbit?
and how do i know what size to buy? hes about 4.5-5 lbs and a dwarf himmie.
I know the H is the best one, but what about the leash part? does it matter?
hes a year old, and he doesnt like being off the ground but if youre just holding him on your lap he will stay there for a bit if hes not wanting to just play the whole time.lol

I personally use the bungee leash from the come with me kitty harness (but not the harness)
http://www.amazon.com/dp/B000OBIW9Q/?tag=skimlinks_replacement-20

and this harness
http://www.amazon.com/dp/B000BHGNFS/?tag=skimlinks_replacement-20

The 9-14 size fits both my 3 lb and my 5 lb rabbits well.

I found harness training my bunnies inside the house did not work. They knew the territory and knew where to run and chew the leash and harness. They hated it. So, I took them outside and attached the harnesses night and secure and then they were so fascinated with being outdoors that they didn't try to get out of the harnesses!

I just ordered the bungee leash from Amazon. The harness I bought at PetSmart doesn't fit so need to take it back & get another one that does. Thanks for the info, Christina. Good luck with your bunny liking the harness & leash. Hope you will post how it goes & pix of your bunny wearing his harness & playing.