I don't have nor played a Roadster, but do have the same TA/2:90 setup as you and have a RK II on Order. I have considered selling the rack setup but, in the past I have come to miss it and ended up paying more to re-purchase.
I like the TA/2:90 for those MKIV tones, which I, under much trial and error believe I've mastered to 99.9999% likeness, enough so that I sold my Mark IV.
My thing now is if I sell my rack setup, I will lose all those wonderful Mark tones I love. I will not repeat the mistaks of the past.
I am going to gig both my rack setup and RK II (not concurrently of course). If I am happy with the tones from the RK II alone then I may consider selling the rack setup, but my gut tells me I will keep both.
Between the rack and the RK II, I believe I will have all of the Mesa tones covered (Oh and I have an LSS too).
My recommendation is not to sell the rack setup and gig both the amp and the rack to make sure the other satisfies the tones you have in your head. Then sell once you've achieved it.
That is of course, unless you need to sell one to finance the other.
For me, I've sold and re-purchased my rack at least 5 times in the last 15 years, so I pretty certain that the RK II and my rack will be buried with me some day in the very distant future. :wink: