Normally I ride alone as well. Quick list of what I take and why:
Cellphone with ICE- fall off and can't get up type of thing,
Backpack- usually I ride bareback or in my flat saddle so saddlebags arent a option. Inside: antibioctics, bandaids, wraps(cold).
Helmet-honestly it depends where im at, if im going around the farm I don't need one.
Wrap Horses fronts- His action is very important to me and a pulled tendon ISNT an option.
Moving on =) my horse has a major problem with serparating from the herd. He bucks(not too bad though), spooks easily, and canters the WHOLE time. But last time we did very well. He did none of these things! When riding with other horses he is very competive. He has to be first ( a habit I think he picked up from me). So we have to constantly circle back to the rear. But end up in front in 3 mins. He was a carting horse before we got him so I try not to ride on roads because he gets....funny. (I promise he's really sweet!) But Berty always does fine for other people!