welcome aboard the ecco friendly super addiction highway. after reading tons of info here i have had some trike ideas .
With the trikes you have you could do a small amout of fabrication and mount a chinese 2 stroke in frame kit with a SBP shifter kit to utilize your gears and solve the sprocket issue in the rear of the trike. That would give you the low end to climb hills and the high end to cruise along. i have seen some kits as low as $130.00 seeing as your doing 2 the SBP kit would be a necessity.
Just my recent thoughts on trikes i am going to build one come summer.
Good luck in whatever you choose
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