Let me start off by saying I think this is a great idea, and I wish I had more of your discipline when I started brewing. It took me a few kitchen sink beers to ‘slow down to speed up’.
SMaSH beers can be tricky though. I think if you are going to go this route, you may be better off going with something like vienna malt, especially if you are brewing 5 gallon batches. As others have suggested, MO or pale ale may also be a good choice. These have a little more character and should yield a drinkable beer, whereas all 2-row may be ‘thin’. Note I have never done an all 2-row batch so I can’t swear to that.
Also as suggested above, it really depends on what you like. I know for me, I liked a few styles when I started brewing, but actually BREWING DIFFERENT BEERS to which I’d had little exposure (or none) allowed me to really appreciate how good a well-brewed example of the style could be, even to someone new to it.
Not knowing what you like to drink, I would suggest a few different categories of hops. Maybe some fuggles (English), Centennial (one of the best all-around American IMO), and something weird like Sorachi Ace or Nelson Sauvin. If you like one category of these specifically, let us know and we can suggest some specific hop varietals.
One thing to keep in mind as well, fermentation (yeast strain, pitch rate, ferment temp and schedule) can have HUGE impacts on beer. In my opinion (though some may disagree), more than most of the other ingredients. Same wort, same hops, same yeast, fermented at different temps, can yield significantly different beer.
Finally, don’t underestimate the benefit of splitting batches (multiple boils/different hops, same wort) different fermenters and/or yeast strains/ferment temps. This can help you learn quite a bit about different components of the process, and if it interests you as it seems to, it can be a blast.
Keep this thread updated and let us know how it progresses, good luck- :cheers: