I have to tow it 150+ miles...rental will have to be a single axle with a total load capacity of 2500#. ...front end in my pickup bed which would leave about 2100# in the tractor and backhoe chained to the trailer.
By "front end", I hope you mean putting the complete FEL assembly in the bed and not simply resting the bucket in the bed while towing. I'd be a little curious on how you are going to get it in the bed.
Regarding the trailer capacity, remember that you have to take the weight of the trailer out of the capacity as well. I've personally towed my tractor in a 5' x 10' 3,500# capacity trailer (1,000# more than the trailer you're talking about) and I have to say that I didn't feel it was safe but for 5 mile trips at 35 MPH. There are many reasons for this not being safe, but the two biggest factors are the inadequate sidewall stiffness and the lack of brakes.
I beg of you not to tow with this rental trailer you spoke of. Beg. Hands and knees.
Put another way:
I would absolutely, positively, under no circumstances whatsoever, feel comfortable with my $20,000 machine in a rented trailer with a capacity of 2,500#. No way, no how. Just too small.
If at all possible, I would contemplate a trailer with your purchase. The absolute bare minimum trailer with one of these machines is a 6' x 14' landscape-style trailer with brakes on one axle and a 7,000# capacity. You could probably get a new one of these in the $1,400 range. The preferable trailer would be 6' or 7' x 16' flatbed with brakes on both axles.
I purchased my 10,000# trailer for $2,500 and absolutely love it. I have put over 6,000# of material on it several times now (6 times, to be exact) and can "power un-load" all day long. I just re-did someones driveway for them yesterday. I dropped the tractor off, un-chaining it in about 3 minutes, went to the quarry and picked up 3 tons of stone, unloaded and spread the 3 tons of stone in about 20 minutes, then spent 30 minutes dressing the driveway with the box blade, then loaded the tractor, properly chaining it down in under 5 minutes. The whole thing, including picking up the stone, took about 2 hours. If I wasn't able to unload the stone with my tractor, I'd spend 2 backbreaking hours just getting the stone off the trailer.
As a bonus, I've saved myself over $500 (conservatively) in delivery charges. Only once could I have saved by a larger haul (my first project called for 6 tons of stone)...all the others would have been seperate deliveries. I will probably have the trailer "paid off" by saving myself delivery charges in 3 or 4 years of use.