I'd love to have a Ranger/Rogue too. Alas, it is not to be. Maybe we get archetypes to cover the options in the future.
Maybe a Rogue archetype that gets some Ranger/Druid casting and a Fighting Style (Archery or Two-Weapon). Rangers are pretty good in Solasta already, so using the Rogue class as the basis would be a nice chance to give us a strong Rogue subclass.
Maybe something like:
Survivor - You gain proficiency with Wisdom (Survival), or expertise if you're already proficient.
Blade and Bow - You gain proficiency with scimitars and longbows. (Note: Two weapon types that fit with Sneak Attack)
Fighting style - You can choose between the Archery and Two-Weapon fighting styles.
Spellcasting: You gain access to spells in the Green Magic list (Wizard Greenmage expanded spell list. Maybe some other spells like Darkvision too). You use Wisdom for your spellcasting modifier. You gain one caster level for every 3 levels in the Rogue class (Note: This is normal 3rd caster progression). You don't prepare spells, but instead memorize a select few spells. You can change one known spell each time you gain a level in this class.
Mark of Death: When you land a Sneak Attack on a creature, you can mark them for death for up to 1 minute. Your weapon attacks deal additional damage equal to half your Sneak Attack damage rounded down (5d6 SA means 2d6, 6d6 SA means 3d6). You can use this ability once per long rest.