Being versatile will get him far, though, because it’s simpler to counter someone who only has 1 skill in his repertoire. Not easy, but simpler.
Having a small back-up water proof Pouch of Holding with emergency supplies and items concealed on himself as well as his Main Bag of Holding would be a very good idea (perhaps with a Concealment Enchantment on it). Also an Expanded Quiver might be useful for himself and Sion (a Pouch of Holding for Sion as well), especially if it's possible to put it into his Bag safely, if not then second thoughts on that might be needed or just a cheap version that wouldn't hurt to much to just dump if needed?
Thus the need for a balance. The right build will take you far. A dozen skills or two dozen skills makes sense given Richter's abilities.
Learning any Skill that will give more general World/Stat Information, more Notification Information, and more Lore Knowledge is a must. As are any Skill that gives Secondary Stat Characteristics or makes it possible to Synergies between different Skills.
I am wondering what the different Exploration Skills are, presumably Map Making is likely one, but what are the others? The Settlement Specialization of Explorer might have granted Bonuses to them. And finding Places of Interest while not a Skill would also likely help. Any idea's what those Explorer Skills might be!
Explore the underway(dwarf, any subrace) Explore the sea(sea dwellers) Explore the planes(planesjumpers of all kinds) etc.