To answer the original question, YES. I do not have MIMA and have exceeded 100mpg and 1000mi on a tank many times, both with and without "overfills." I must point out though that you have to be careful about comparing your results with those of other drivers -- there are a lot of variables to consider and routes can play an enormous role.
I recently changed job locations and my route is both shorter and less conducive to high level hypermiling (higher speeds, more traffic, bad placement of lights which are difficult to time). Traffic had gotten much worse on my other route so the numbers weren't nearly as high (I only breached 130mpg once this summer but I did it many times two summers ago on the same route), but I could still get up into the 120mpg range on the way home... no more. I've only been on this route 2 weeks now but so far my max trip in was 112.0mpg and the max back was only 108.3mpg. I can probably improve those a little with more familiarity, but all other routes are considerably worse. <shrug> That's just the way it is these days. (I'm averaging right around 106mpg for the RT most days -- the other route was good for 112+mpg RT)
Is it possible for
you to exceed 100mpg? Sure. You are close enough right now that I'm positive you have the skillset necessary. Will your route allow it? That's a different question and one to which the answer may be "no." There is only one way to find out -- keep trying.
For techniques, I'd like to echo Red1Dr -- there is a speed at which other drivers will perceive your vehicle to be slow enough not to bother harassing. My experience indicates that this speed is somewhere around 7mph under the posted limit -- it varies a bit from place to place and at different times of day. Once you find it and people start going around you, it isn't much trouble. I drove all the way to Elkhart, IN from Minneapolis at an average speed of 53mph without any issues to speak of because of this.
For other techniques, watch for tail-lights (and even reflections of tail-lights!) to get an idea of what state out of sight traffic lights are in. Use downhills and flat sections of road before hills to gain more momentum to help with climbing at a higher instantaneous fuel efficiency. Give P&G a try in the lower speed sections with close lights -- in the range from 25-35mph it can give higher results in variable traffic than lean burn can. Just accelerate in 4th gear at about 50mpg and you should be able to stay out of assist, get up to speed reasonably, and get some decently long glides (engine off) out of the car. I recommend not using the CalPod switch while doing this as the car seems to use a little background regen when accelerating to keep the SoC topped off.
Good luck and don't give up!
