Caribou Ranch - Near Nederland

This is such a gorgeous place to ride in the summer and fall that isn't a far drive and has some idyllic scenery.  It is a perfect beginner trail, especially for those horses who dislike bikes, but is so beautiful that any level rider would enjoy it there.  
Trailers park in the Mud Lake parking lot and there are some nice pull through spots that can handle 4 to 5 trailers.  There are bathrooms in the mud lake parking lot next to the trailer parking that we have always found super clean.  From the Mud Lake parking lot there is a .7 mile trail called the Caribou Ranch link that takes you to Caribou ranch.   There is a 4' wide very non intimidating bridge that runs about 30' long and spans several marshy areas on this trail, so make sure your horses can handle a little bridge work.  Once you get into Caribou Ranch, you will have another bathroom opportunity in the parking lot before hopping onto the Bluebird Loop, which is a 1,8 mile loop on a nice wide and evenly footed trail that goes in and out of the aspens - amazing in the fall!
I have taken barefoot horses here with no problems, on our tender horses, we do boot their fronts as there is one little rocky section to get down on to the loop.  We have only gone here on the weekdays and I have heard the weekends can be super busy, typically we see only a few other hikers on the weekdays.  I am pretty sure we have seen some sort of wildlife every time we have been here, usually deer on the loop, but we have seen Moose and Elk on the drive up a few times.  
The cell service is spotty,  but I know I have had my phone ring a few times here - so there are a few areas of service.  
Overall - A very beginner friendly trail, a long bridge to cross, no water crossings, wildlife, no bikes or dogs.  
Bring with you - Bug Spray, water, snacks, and a camera!
Things to know - Caribou Ranch is closed from April 1st to June 30th for wildlife

https://bouldercounty.gov/open-space/parks-and-trails/caribou-ranch/