Either arcane archer or myrmidarch magus. Those are your only avenues.
There's also Eldritch Archer Magus, which is better than myrmidarch is pretty much all respects.
But yeah, only three options.
Arcane Archer prestige class -- can get 9/9 spellcasting, but takes quite a while to get the Arcane Archer levels online. Precede with Elcritch Knight prestige class so you can meet the BAB requrement faster.
Myrmidarch Magus -- really meant to be a switch-hitter rather than commonly using a ranged weapon, although trading out Spell Recall and Greater Spell Recall to get Ranged Spellstrike really hurts on top of Diminished Spellcasting; still, unlike any other Magus archetype, you get Weapon Training (as the Fighter class feature), which became a LOT better with the release of the Weapon Master's Handbook. Also gets Armor Training, which became significantly although not as impressively better with the release of the Armor Master's Handbook, and the only other Magus archetype that gets this is Armored Battlemage, which is just not very good (and doesn't get Weapon Training).
Eldritch Archer Magus (not to be confused with Eldritch Scion Magus) -- this and not Myrmidarch is the archetype specialized in attacking with a bow -- not only do you get Ranged Spellstrike (without trading out Spell Recall or Improved Spell Recall), but you also get Ranged Spell Combat; unfortunately, you also lose the normal Spell Combat. Is legal combine with Myrmidarch, but it's not a good idea (this gets you 2 overlapping Ranged Spellstrike abilities, from trading out different things).
Spellslinger wizard also works, albeit with a gun instead of a bow. Some people think that spellslinger 1 / another caster X is the best way to use it.
A conductive ranged weapon and some sort of ranged SLA or supernatural ability - like those generally useless 1st level sorc bloodline abilities - could work, though it wouldn't be a big upgrade.
Edit: forgot one. An arrowsong minstrel bard gets a form of ranged spellstrike at 6th level and a bunch of other useful abilities for archery at other levels.
The spell Named Bullet is only going to appear on a Wizard or Witch based Eldritch Knight at level 9, but it's an awfully nice way to magically make an arrow completely murder something that you know by name. Nothing like creating a couple of touch-AC auto-crit bonus-damage arrows with the boss monster's name on 'em.
Spellslinger wizard also works, albeit with a gun instead of a bow. Some people think that spellslinger 1 / another caster X is the best way to use it.
A conductive ranged weapon and some sort of ranged SLA or supernatural ability - like those generally useless 1st level sorc bloodline abilities - could work, though it wouldn't be a big upgrade.
Edit: forgot one. An arrowsong minstrel bard gets a form of ranged spellstrike at 6th level and a bunch of other useful abilities for archery at other levels.
The only thing keeping me from playing an Arrowsong Minstrel is that it doesn't combine with Sound Striker. A pretty good archetype for a bow-bard, though!
On a related question, can a three-armed Magus Archetype Eldritch Archer take wand wielder magus arcana and spam a true strike wand held by the third arm every round to shoot an arrow in that round?
Yeah, it could. Technically, that's just modifying Spell Combat, so it would be activate the wand, take a full attack with the bow. Only the first arrow would get the benefits of True Strike, but it would work.