The transatlantic trip (via Iceland / Greenland / Newfoundland as usual) has been done, in singles, thousands of times by ferry pilots. Apart from the acceptance of slow or unlikely rescue, and the need to carry/wear survival gear, it is just sitting there on autopilot for many hours.
An IR helps a great deal, I gather, because a lot of the airspace is Class A and you definitely want to be as high as possible, but the same is true for much of Europe land-mass anyway.
A C182 will totally beat a TB20 on short field capability, and so will many other types. A Maule will get airborne in the
width of many runways
But you wouldn't buy a TB20/21 for operating from a 300m grass strip. You would buy it for 800nm trips across Europe, in comfort and style and stability in turbulence under IFR...
A plane which has the short field capability of a C182 and the comfort/style/etc of a TB20 would be a small unpressurised turboprop, and currently nobody makes those. Arguably, the nearest anybody got to that in recent years is the
Grob 140 but that project is almost certainly dead. Grob's test pilot got killed recently and they are working on their "light jet", just like everybody and their dog. The G140 was too expensive anyway.
Until somebody does something like that, we will have to choose. You can find them in the USA, in the Experimental category.