If you really want to go the extreme, being that you live in the chicagoland snow belt, don't drive it at all in winter. Just park it in the garage from Dec-March and get yourself a winter beater. A lot of my friends park their hot rods in winter and many of them have never seen an ounce of road salt. Makes a HUGE difference in maintaining the longevity of the vehicle.
One thing about garages....hopefully you have a concrete slab that was poured on top of well-drained gravel, not organic topsoil like mine. My garage sweats moisture so bad that at times its probably better for my vehicles to be parked in the driveway...
Sounds like your floor was not properly done. A properly poured garage floor should have a layer of gravel to allow the slab to "float" then a vapor barrier needs to be put down and the people pouring the floor need to be careful not to puncture the barrier. IIRC, that's what's in the building codes and recommended by the American Concrete Institute (ACI). Sadly, too many guys try to cut corners and skip the gravel and vapor barrier... or just dont' know any better because they never learned how to properly do concrete work. Drives me nuts that I have to bid against morons like that...
But anyway... on to the OP's questions...
If possible, store it in a garage during the winter months and drive a winter beater - that will go a long way towards keeping it nice for a LONG time.
Use good synthetic fluids and change them at the regular intervals. There is no need to change synth oil at 3,000 miles - even 5k is usually a little early anymore. Use a good filter too - I run only Motorcraft filters.
I stand by breaking in a motor properly. Drive it easy - no stomping your foot to the floor for the first couple thousand miles. Try to avoid towing/hauling too. And change the oil and filter at the first 2,500 miles, then again at 5k. I did that with my Ranger, it got babied till after 5k. And my fuel economy numbers (on pure gas, something that you can no longer get around here) showed it. With a 3.0L, 5-speed and 3.73 gears I was getting 19-21 mpg around town with a cap on the back, 21-23 mpg around town with a tonneau cover. Highway was 25-31 mpg. Yes, I hit 31 mpg with a 6-cyl truck on the highway. Now with this ethanol blend crap they pass off as gas, I'm stuck down around 17-18 mpg around town and 21-24 mpg highway.
Spray in bedliners are good, but if you're going to do a bit of hauling with it, you might want to consider a hard bedliner and rubber bedmat approach.
I had the fabric protector stuff put in my Ranger when I got it. Then I got some carpet remnants and covered the entire floor with it and put some floor mats down for the driver and passenger. Pull up that carpet and the factory stuff looks like new - 10 years and 85k later (and I used it for work for a few years, lol). Seatcovers are a good idea too.
Wax on a regular basis with a quality wax. I prefer Meguires Gold Class.
DO NOT use a spray-on "rubberized" undercoating. It makes a mess, some places don't prep or get things sprayed good, and you have to re-coat it every year or two because the stuff will dry out and crack. Once moisture gets behind the coating and starts to rust, it'll spread like a California wildfire. I put an electronic rustproofing system on my Ranger and it worked ok, but I wasn't overly impressed with it. I'm going with oil coating from now on. There are a few places around here that will oil undercoat, but if I can't find anyone I'm gonna just spray it with old hydraulic oil on a regular basis. Oil will not let it rust.
Try to avoid eating in the cab too. Beverages can be ok if you're careful with them - but it's usually best if it's nothing more than something like water.
And whatever you do, DO NOT smoke in the truck. You'll never get the smell out without replacing the entire interior. My rule is "if you NEED to have a cig, have it before or after you get in the truck."