The Tercel with the 5E-FE was meant to do 45mpg highway. So if it's geared different, sticking a tercel final drive in it might get good numbers.
I remember The RoadWarrior..To understand who he was, you have to go back to another time..the world was powered by the black fuel & the desert sprouted great cities..Gone now, swept away..two mighty warrior tribes went to war & touched off a blaze which engulfed them all. Without fuel, they were nothing..thundering machines sputtered & stopped..Only those mobile enough to scavenge, brutal enough to pillage would survive. The gangs took over the highways, ready to wage war for a tank of juice
I also have the 1.5L Toyota engine in my Scion xB. About 300lbs heavier than the Paseo and my last fill up I got 38.8MPG. We'll see if I can repeat it to verify it wasn't a fillup fluke. So I imagine on your Paseo you should be able to get above 40 pretty easily!