Just curious, you stated 5K axle or is that 5k load capacity?
Just making some guesses here, so please do not take my math as gospel,
The trailer probably weighs 1,200#
The tractor empty guessing 1,600#
Adding fluids and if you have tires loaded, guessing another 400#
Mower deck guessing 300# depending on size of deck
The loader arms, guessing 600#
Guessing pallet forks around 250#
Those above have a weight of 4,350#s.
I don't know how much a backhoe weighs so this is just a huge guess, but guessing 600#s and that would vary depending on buckets size.
So just throwing numbers at it, it looks like you will be right at your trailer limit or maybe a little over.
Again, this a guesses, I would be curious to know how close I come, but don't use these numbers to determine if it is actually safe or not.