[Diesel_Dave]

To start off with, I'll admit that I haven't thouroughly read though every post on this thred (but did skim through them).

Let me start by pointing out the magnitude of the goal that you're trying to accomplish (>=30 mpg). That's close to double what you're getting now. That being said, I know it's possible, because I do it on a fairly similar vehicle. But, with there's also a reason I'm the only person I'm aware of whose done it...it ain't easy. Keep this in mind.

My first piece of advice would be not to get too far ahead of yourself. Sure, you want to go from 18mpg to 30mpg, but the first step is going from 18mpg to 19mpg, then to 20mpg, etc. While the big "out of the box" ideas are flashy and fun (and soemtimes very good), most of the people on this site will attest to the fact that their journey has been mostly one of small, incremental changes that add up to something big.

It also seems to me that you're overlooking driving mods. IMO, these can easily give you a 30-40% boost from where you are now. It sounds like one thing that you've got going for you is a long, consistant commute. This is a major plus for improving driving. Start keeping a journal/log of each day, what you did differently, and what the FE impact was. I assume your '01 has an in-cab mpg display--it's not horribly accurate but it still makes and excellent guide (i.e. higher numbers are better). Here's what will happen, you'll do something (either intentionally or unintentionally) and one day you'll get really good mileage. It can be a different route, a different shifting pattern, a different cruise speed, etc., but after you learn what it is you can learn to do it over and over again--and beforehand you never would have guessed that it made such a difference. Records are also of extreme importance for this quest of yours. I can't emphasize this enough. It's the only way you'll learn what's working, what's not, and where to focus your attention.

What is this commute of yours like? Interstate? City? Rural highway? Mix? Flat? Hilly? Many other vehicles? This will affect what things will be the biggest gains.

As far as the hybrid idea goes, I'm not to keen on it. A hydrid has the potential to benefit you in two primary ways: regenerative braking & keeping your engine in "better place" on the BSFC map. You can reap most of the benefit of both of these with careful driving. If you do the "driving wothout brakes" technique, which you try to minimize the use of braking you don't need regenerative braking because there's no energy to recover--which is even better than regenerative braking. This is key for getting good in-town FE. With a big truck like ours, you can loose a lot of energy to heat and brake dust without realizing it. Learn how to time red lights by coasting in neutral, adjusting your speed, looking at the traffic ahead, etc. Not have to brake to a stop and then use lots of fuel to get back up to speed is huge. Also, when you have unavoidable stops like stop signs, learn how to coast in neutral down to a fairly slow speed before you ever have to apply the brakes. And with regard to the "better place" on the BSFC maps, you can take care of that with shifting patterns, keeping your rpms down. I'd encourage you to try running lower rpms when unloaded. These engine have somewhere near 400 lb-ft of clutch engagement torque (max torque at idle speed), so you can run pretty low rpms unloaded without lugging the engine.

I'll probably chime back in on some of your other proposed mods, but those are my thoughts for now. I look forward to seeing how you do, and helping where I can.

And start a fuel log so we can see how you're doing.