I agree with everyone here. We try to desensitize to lots of objects - not so much because you can desensitize to everything but because yes, it helps them learn to "think" about spooking and not reacting and it is also one less thing for them to react to.
We also drive with halters on under our bridles. When we rode, the lead was tied around the neck in a cavalry knot. When driving with a harness that has a collar and hames, we will leave a lead rope attached to the halter and wrapped around the near side of the hames. On a pair, the right side horse has lead rope on the off side hames. We will also carry an extra long lead rope or a lounge line tied to back of seat on either cart or wagon (has been used 2x to pull a heavy cart stuck in the mud loose w/o being in the muck with it - after the ponies unhitched) - allows for tying to extra large trees on our driving paths, too.
We try to let someone know approximately when we will be back and where we *think* we are going to be going. If we have a change of plans, now, we use our cell phones to notify someone that we've changed up. The trails we used to use - cell phones and GPS tracking were non-existent - however, both of those farms with extensive trails have been sold to non-horse people and the horse trails and campgrounds at both have been closed.
The Moss Foundation, in Southern Pines, is one of the places close by we can still go to - haven't been since well before we moved. Again, certain areas both GPS and any texting/calling didn't work in, though did in some. We actually have areas on our 21 acres where there is NO cell reception & we are putting driving paths thru those sections, so it could get interesting.
We are currently in TX (middle daughter & I flew in; youngest daughter drove up to MT first to visit with my mom; oldest daughter/family didn't make it - it's my Dad's 75th Bday and we will visit again today). While on her travels up in the Dakotas and across MT, Sierra (our youngest) discovered that even with Verizon and the newest phone - NO CELL worked anywhere when not in *major* cities. She actually went into media withdrawal - but she also mentioned *wow, how would you call out with a horse accident?* when she arrived here in TX last nite. I told her we had *walkie-talkie* radios when we lived in MT. Still didn't work deep in a canyon or arroyo - have no idea how Chanda (chandab) does contacts...
Knife, water (at least one bottle on the cart - in the wagon I carry a small bucket that will hold several bottles), couple of band-aids & neosporin/bacitracin in ziplock baggie, BUG SPRAY!! - Woods OFF - carried on cart for both humans and ponies- carried in saddle bags when we were riding; I use my whip to dislodge any persistent bugs that insist on landing/biting. Deer fly bites are painful and will drive both horses and ponies "mad" enough to ignore reins, lines and "whoas" if not careful.
Think that's it.