Casa Fantini is the point of arrival (or departure) of a path that leads near the cave and then climbs to rejoin the Via di Gaibola. Doing it uphill is for hikers, even with the e-bike it is certainly challenging and probably requires you to go down and push in a few stretches. In any case, the best of himself is given in descent starting from via di Gaibola (there are tracks in some laps that I have saved and which have the name "Fantini" in the description).
Immediately after the downhill start there is a climb that is quite technical and above all muddy if it has rained. After the descent it is technical and fast, in particular high enough there is a very steep but short descent on the ground to be faced with attention to the weights (out of the saddle) and where I suggest to give up. The descent alternates on the ground and on gypsum rock, but there is no shortage of roots .... in short, forget to sit on the saddle!
Arriving at a sharp bend (there the path forks and I believe that part of it heads towards Via dell'Eremo), a second, even more technical stretch begins, where in particular about halfway down the descent there is a small drop if you holds the right and must be tackled by further lightening the front if you go slow, otherwise you fly it. At the end of the path, keep to the left that goes towards the Fantini house, because on the right the road is closed by a chain ..... before reaching the house there is a series of well-spaced steps to go out of the saddle and enjoyable for those who it has a cushioned bi ... otherwise keep the left to the side of the steps.
I do not recommend doing it after it has rained and if you see that there are muddy areas in the surroundings, it is guaranteed that you will find it there too and it will not be much fun if you do not have soft tires that are also suitable for muddy terrain. Beware of hikers, at least the three times I have done the path I have always met them in several places!