You don't need a track and cars unless you're racing
- cruisers tend to use the auto-pilot mostly and no robot yet can operate the traveller
The proposal of just one fixed point will probably not suffice, but three such points can (equating to middle track point and outer track points for moderate and heavy conditions). I've seen that used and the cruisers are happy.
option is round mild steel
bar (8mm-10mm maybe would do) bent to shape. Maybe a metre of horizontal (or slightly arced) with vertical legs with welded flange for attachment to the deck
each end. A simple block on the bar can ease the friction if necessary.
Lots of older boats have this arrangement and it works well; the H28 and others in that era, right up to big steel
dinghies often have much the same arrangement (in rope).
Tracks and cars and all that gizmo are important for racers, because the traveller is an important control. But for cruisers it's an unnecessary expense imho...