I do trails on my dressage horse in my dressage saddle it's super comfy
My friend who rides only on the trail swears by custom sadderly dressage saddles. Riding with her has always been super comfortable for me! For steep terrain the leg blocks are awesome.
For me, English saddles are more comfortable to ride in than western but it depends on the saddle. If you've ridden in the saddle before and like it then yes it should be fine. After my dressage lessons I usually take the horse out on a hack as a cooldown and find it to be quite comfy :)