I've been bringing my yellow lab with me riding since she was a pup! Almost 6 years ago! The only thing I suggest is making sure he/she listens to your commands. I taught mine to get off the trail when other riders approach. I also recommend you teach him/her to "do their business" off the trail. My pup started doing this automatically without my having to teach her! Lastly, teach your dog to drink out of a water bottle. I ride with a Camelback for me and 2 bottles for the dog! I also let her swim wherever there is a stream crossing or a big mud hole with water in it. You don't want to overheat your dog!
With that said, most other people love seeing her run with us, and always enjoy petting her at the car or while we rest! There will always be a few "jerks" out there that will make a rude comment, but they've been few and far between. (Like 4 so far!) The only problem I've had is taking her with us at State or Nat'l Parks. There is a 6'0" leash law, but most Rangers don't enforce it if the dogs well behaved. I usually take her leash and loop it over my shoulder/head while I ride, so it's available if I need it!
There is one trail in the area I've never ridden b/c they strickly prohibit dogs, but there are others nearby, so I don't let it slow us down.
Good Luck & L8R
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