You have to decide what compromises are best for you.
The ks-2, 55-300 plm and the 1.4x tc is best for me. I go on local park safaris every day. I ride my bike to the park with just that combo on my camera around my shoulder. I do some post to clean up. This is a typical shot. I had to use a 2000 shutter to stop motion and ISO 2200. I still cropped the height down to 57% original frame on my ks-2.
Here is another "safari" shot in winter light. at 364mm. (364mm gives f/8, any longer goes to f/9.5) at 1600 shutter and 400 ISO. The coyotes are about a football field away. This is not cropped.
granted that I don't print many and they are for documenting and remembering the moment mostly.
I did print this one to hang in the bathroom. It was shot at 266mm so I didn't need the tc.