Depends. If you want to go 2h spear I’d pick Hop2 -> Cata3 -> Lancer or Highlander 2 -> Cata 3 -> Goon1 -> Lancer.
If you want to go 1h spear + shield (without Murmillo) I’d go Highlander 2 -> Hop3 -> Dragoon 2 or Highlander 3 -> Hop2 -> Dragoon2. Switch Highlander for Peltasta if you want to be more defensive (I wouldn’t recommend Pelta 3 tho, seeing the dmg would be quite bad without Murmillo).
You can also make a Hoplite Murmillo which go together very well, but if you want to avoid Murmillos then Dragoon2 is a nice choice.
You can also try a spear variant of shinobi but I don’t have much experience with Hoplite -> Shinobi (and you’d have to do hidden quest too).
You can, of course, give up on Cata 3 for a Lancer build (going Sw3 -> Hop3 -> Goon1 -> Lancer for example) which deals considerably more dps than Cata 3. However, upcoming kToS patch that’ll buff Rush’s area, AoE atk ratio, and +30% damage while Lancer’s Initiate is up, will make Rush much more powerful and more worthwhile to pick in a Lancer build. Rush doesn’t have tons of damage but it’s still a decent AoE skill (good in dungeons and such).
EDIT:
It’s going to be very hard to have both good mobility and tankiness from hoplite. You could try a Cata 3 -> Hop 3 build… But I’m not sure how well that’d go…