You probably don't need any levels in Rogue at all. You could if you want to, but there's not a whole lot of benefit. Ranger already gets 6 skill points per level and a nice list of class skills. I ran a single-class Wood Elf Ranger in my first playthrough of SoZ and was very happy with the result. I went the archery route, but two weapon fighting would work well too. That looks pretty solid. If you're going to multi-class Rogue somewhere, the Fighter or Paladin would be the best candidate since they appreciate the extra skill points and class skills, and get more mileage out of sneak attack since they have an easier time getting in the thick of things and managing flanks.

Able learner feat, so you can pick skills outside your preferred ones.
I'd usually pick at least 2 levels of rogue to get evasion.
Taking 4 levels lessens attack bonus by same amount as taking just one, so might as well take 4.

Though, as mentioned, just taking ranger is probably more powerful.

Dex based ranger is more durable, at least if you're sticking with light armor as is required for the ranger feats to function. STR based tends to do more damage though.

Dual wielding is more effective in late game, where you can pile up enchantments on both weapons.
Early game it's rather more practical to keep attack bonuses high, meaning 2-hander or weapon+shield.

Taking a level of fighter for cleric just to get tower shield, meaning +1 to AC, is not a good trade.
1 more spell level is much preferable.

This would definitely be a must-have feat if you multi-class rogue, since the additional class skill list is the real selling point. Rangers get evasion anyways at the 9th level in NWN2. It's one of the big dissonances between the Ranger/Rogue class combo. The nice thing about dual-wielding rangers is that they don't need to meet the strength score prerequisites for their feats. The loss in AC kinda sucks, but as part of a larger party you can get away with this quite easily since an offensively-oriented party will eliminate and neutralize enemies before they have the opportunity to do much damage. Tower Shield is 2 additional points of AC over the large shield in NWN2, but it also incurs a -2 penalty to attack. While not completely untenable, I'd agree it's not worth it.

Thank you. So, pure cleric and dex based ranger. Do I even need a rogue, or am I better off using an NPC pick locks and disarm traps? If I multi class the fighter with 2 rogue levels, does that gimp the front line capacity? Iwould need to focus on strength, dex, con and int to get enough skill points.

Which build would I use Able Learner with?

Fighter/Rogue is a superb combo (Paladin/Rogue would be, too). You can actually invest very heavily in Rogue levels without seriously impacting your front-line abilities. While your accuracy does drop a bit, your damage output rises due to sneak attacks. You can go as extreme as a 4:1 rogue/fighter ratio and still be a totally competent front-liner.

If you pick Able Learner you can learn cross-class-skills as if they were class skills, so you can make your ranger a perfectly competent lockpick and trap disarmer.

Also, ranger/rogue is a perfectly good multiclass option, especially if you decide to go light armor dual-wielding route. Even gets some more skill points from ranger levels than the other multiclass options.

It's just that Fighter, Paladin or Barbarian make for slightly more powerful options for rogue multiclass, significantly so if you don't make use of the rangers bonus feats.

Also a thing worth knowing. SoZ will throw your way potential ranger and druid additional companions, so wilderness skills are covered right from the start. (also other companion options.. but I think they came later).

Thank you both very much.