Hey Dog, I have to appreciate the enthusiasm 
I'm not exactly sure where you are headed or how you are getting there but let me offer some responses:
1.) reduce wheel dia. and mount lower profile tires within reason to lower the relative effective gear ratio of the rear-end or trans-axle. this may also improve aerodynamics too, by lowering ride height.
Cutting the springs may be a cost effective option for reducing ride height too. Taller skinnier tires is a way to get a little more ratio without swapping gears.
2.) better air filter
Probably no good, least not on a fuel injected or feedback carb setup. I know Darin has researched it.
3.) on the exhaust side; header(s), free flowing catalytic converter, muffler
Again, this is not money you would be spending for economy.
4.) replace camshaft with one that develops torque at earlier rpm range ( they used to call RV grinds )
Might be able to advance the existing cam (or just the intake one) too by modifying the cam gear/sprocket slightly, and doing a lot of head scratching.
5.) have automatic trans modified or replace with manual unit
+1 on a manual swap, enables even more reliability and efficiency and enhanced techniques. Otherwise might be good to be able to force high gear and lockup at lower speeds with a switch or something.
6.) lower rear-end or trans-axle gear ratio ( example: 3.73:1 to 3.42:1 or 2.73:1 ), keep in mind a lower gear ratio requires more torque, but that's where the smaller dia. wheel and tire package really helps out
Your 85 'murrican block is silly with torque already 2.73 if you can find one for cheap, and do some aeromods to compliment it.
7.) install a second battery, battery selector switch, alternator cutout switch, and a solar cell battery charger, ( most of these item's preferable marine grade, deep cycle hold a charge longer, selector switch should be able either battery, both or off, also acts theft deterrent, alternator cutout should be rated twice the ampere output, and suitable fused )
I use a trolling battery (not trolling/starting) on a 1.9 liter saturn with no probs, you might get away with it, but not a top of the list thing.
8.) now lets add a gauge package: vacuum, amp, second voltmeter, fuel pressure, and transmission temp. ( vacuum can be labeled fuel economy, amp lets you know the batteries state of charge or discharge, should be selectable to either battery or wire in a second one, and transmission temp. helps with peace of mind whether auto or manual, after pricey mods )
You can probably do much better than a vacuum gauge for fuel feedback these days
9.) lets improve lubrication: aftermarket oil coolers for engine and trans, even additional engine, plus trans fluid filter.
Not for efficiency, you should be making less heat once you relearn how to drive again 
10.) if equipped to handle E85, change fuel system components: aftermarket fuel cell, fuel pump, fuel pressure regulator, fuel line (combination stainless steel and flexible braided), aftermarket fuel delivery components rated to handle E85
note; there have been a couple of published studies done on the effects lower grades ethanol blends on non E85 equipped vehicles
If you are so inclined, sure.
11.) suitable used laptop with software to benchmark, monitor, and troubleshoot:
Go for it, where you gonna get your data? Don't know if you are aldl or not, or fuel injected or not for that matter.
12.) enhanced driving techniques for r & d to pull it altogether
Actually I would START there See what other people are getting in similiar vehicles in similiar conditions.
Future mods would most likely include engine rebuild, balance and blueprint, rework, port match and bench-flow heads
Not a big gainer for low rpm work.
l8r