Here's how I optimized my Townie for max speed, yet max slow climbing ease. (I'm an old man.)
In MTB style, I replaced the chainwheel/crank with a 22t/48t combo (the max spread that 4-bold 2x setups can take these days.)
Then with 2 cassettes combined (cogs & spacers from the 8sp CS-HG51 11-30t and the 9sp CS916A HG-400 12-36t) with a Wolf Tooth 42t for Shimano, I made a custom 7sp cassette to go with the original Townie 7sp shifter.
Result is 42,36,30,24,18,13,11 to make the basic 1x7 setup on the 48t chainwheel. I removed the left shifter and front derailer for simplicity and low maintenance. If I ever need the 22t/42t ultimate granny combo, as bailout gearing, I use a plastic tire wedge to ease the chain over. Made sure that the 11t fit into a recess on the 13t cog, and that 8sp spacers were used, to assure smooth shifting up and down.
Gain Ratios on a Townie for this setup on Fat Frank balloon tires are as follows...
8.07x, 6.83x, 4.93x, 3.70x, 2.96x, 2.47x, 2.11x, and for the granny: 1.06x with 170 cranks. (mechanical advantages, petal cycle vs tire tread cycle.)
(I cruise in comfort with a wide upright seat, backrest and ape-hanger handlebars.)