It's more up to the dog then you. Adults in the ABC run either as Gun Dogs or All Age dogs. It's easier to bring an AA dog in then it is to push a Gun Dog out. My dog started out as a GD before she started ranging out to AA range. The trainer let her go go more and more as she got older and now she's given full range. But, she knows the difference between hunting and trialing. It's not uncommon for her to make 800 yard casts off of a horse, but she typically stays inside 200 off foot when hunting. In other words, don't be afraid of an All Age dog to foot hunt off of. If you don't have a horse, you will mostly be limited to walking Gun Dog trials. There are several around the PNW put on by several different clubs.