CTC near me has a motorcycle section
but Rotella is not there as it's a truck oil
I use T6 5W40 synth in my bikes
T6 is....Rotella.
RotellaT (or whatever they re-branded it, T4 or something now) is indeed a full dino diesel engine oil, but eleventy million motorcyclists have been using it with great success for many, many years. Myself included, in both bikes.
All CT's have a basic powersports aisle. And yes, almost (see below) every oil you could ever possibly want, in every different flavour.
On the topic of Amsoil, all our local CT's stopped carrying it. Back when I had Jetskis I used to buy the injector oil there all the time as it was a good quality product, but then it went away, along with all their other options. YMMV at the store level, but at the chain level anymore I think it's history.
As for K&N, I'm no fan of their products in general - a lot of marketing, not a lot of real world benefits aside from removing more $$ from your wallet. OP, get an OEM filter - CT even carries a small selection of MC oil filters at most locations, but you may need to ask as not all stores have them on the shelves.