The main shtick for Swift Hunter is getting the Skirmish damage to favored enemies, which might not be possible any other way depending on interpreting effects that allow the character to deal crits to stuff. For gestalt, the stacking shouldn't work but the skirmish should and for a feat might be well worth it if your player wants to skirmish a lot.
You may want to look through
Alternate Class Features to see what ACF's you'd allow the player to have. Since both the scout and ranger get evasion, it's recommended to swap one of them out. Either can get Spell Reflection for example. The ranger's wild shape variant would certainly be interesting too.
If the player isn't interested in spells, going spell-less and gaining bonus feats from Complete Champion's ACF would be reasonable. The Complete Warrior ACF only grants fast movement and some piddly extras.
For stealth, the
Darkstalker feat will be quite useful.
Entangling Exhalation will help thanks to DFA, if the player is so inclined.
You mentioned your player doesn't care for spells. What about invocations? DFA has invocations right up the stealth alley, including at will Invisibility through Walk Unseen. Draconic Flight will help to get around and start hitting with the breath weapon while flying and invisible. The technical wording on invisibility states that attacks will break it, including damaging spells. Most don't include spell-like or supernatural abilities under that umbrella, and since the DFA's breath weapon is supernatural, it wouldn't apply. If you think that's too much then you can nerf it so the breath weapon cancels invisibility.
Something I just thought of asking: What PF rules are in effect?