I don't use 2nd OD every day certainly; but it does come in handy on occasion for things like driving hard on twisty mountain roads, or maximizing acceleration in a straight line. Sure, using the overdrive means it will wear out quicker; but that's true of the whole car. If you are looking to minimize your driving costs, I'm afraid you've got the wrong car. It's not about miles per gallon, it's about smiles per mile. The only problem I've had that I directly attribute to 2nd OD is that a previous rebuilder either didn't check the pressure or didn't get it high enough. But he never said he did it on purpose, just "Ok, bring it back and I'll fix it."
What I did was to transplant the shift rails and forks into my original top cover, so I could keep the dipstick. Others have drilled out the later casting for the dipstick.
But, you need to get under the car for routine maintenance anyway; so it's not that much more hassle to jack up and support both ends (to get it roughly level) and check the gearbox oil through the port on the side. Then you can grease the front suspension and check the rear axle oil (etc) all without having to move the car again. I try to go through all that at least once a year (or about 12,000 miles for me), but it doesn't always get done on time.
BTW, HF has their 6 ton jack stands priced at only $40/pair at the moment. Their 3 ton stands ($24/pair) will certainly do the job, but sometime I need the extra height.