o I'm pretty certain that I would run The Olden Lands using a combination of For Blood & Coin, Basic Fantasy RPG, and 2e/3e/4e Gamma World.
o Mishlers' Demigods pdf is too good not to use with this. The ST:OS Space Gods and Star Wizards (popularised by some G+ fellows whose names escape recall) angle to space explorattion was not the one I was taking, but my path curved back and I see their truth; its expressed more in Series 2 Space: 1999 (Maya the Metamorph, etc.), where like Kirk before, Koenig wasn't taking any alien guff; after the reality breach-reset, Alpha'd had more than enough warring factions action in Series 1. Demigods would exist to be toppled like the gods who fall under Stormbringer in Elric's stories.
o With For Blood & Coin, I'd use 1e/2e and permit all of those classes without concern. The social and crime angles of 4B&C are right up my glass strewn unlit gangland alley and wildmagic-wastelands ruin shared by multiple different humanoids, a robot, and your group as they ride out a glass storm.
o Basic Fantasy RPG is hands down my consistent top pick for fantasy gaming. Coupled with the optional rules and expansions one has all the classes and the means to make endless variations. The version of a Confessor in BFRPG rules is wonderful and liberating -- the number of variations on the theme with other controlling or redirecting magic powers (not spells), etc.
o Gamma World would supply the Artefacts and Treasures which are paramount importance in collecting XP. As per GW1e: when a tie needs breaking, or some other advantage decided, the character with the highest XP total would win.
o The Olden Lands would be the Pre-Cataclysmic World of Wonders. We know things that were Ancient to the Ancients, what they called 'twice or thrice Ancient' knowledge. They believed that Humanity had faced prior devastations and the survivors would serve as our Ancient ancestors.
o We will, in turn pass on the torches of reason and science. We employ Mutants, both our Humanoid cousins, and the mutant animals and chimera formed in the protean pits of war targets. Together we build civilised lands out of the wilderness and ruinscape. Towns and Cities, Forts and Ports, Farmlands and Forested Preserves where strangers and outlanders travel to purchase goods and consult experts, carouse famous dens of iniquity, or climb a local landmark, etc. The free exchange of knowledge and the redevelopment of fixed type printing will have similar effects, but with less history, and more savagery, how will the wilds be won?