Approached from the south. After the dog leg in the road, there is a turn off and a gravel road leads in the direction of the valley. Decided on approaching from here rather than the valley that splits Monte Catello and Don Marco, because I wanted to see a bit of the path for the approaches to other peaks.
So. Parking at the end of the gravel road. Heading up rocky but used path up valley crossing (non existent in November) stream twice. From here, we carried further up the valley than intended (the actual path wasn't taken as it initially goes off in the other direction before switching back, as I established on the descent). So climbed up side to regain a path get first to a small camp with cows and horses on the sella, and then, crossing over a small prominence, to the base of Don Marco. Here we traversed the side of the mountain through thick woods. Paths overgrown. Eventually came to clearing that lies in between the two hills. Darted up Catello, which was relatively straightforward, then returned and went up the much more difficult section of few clear paths and thick forest to reach the unremarkable summit of Don Marco. Fearing returning such a way we descended directly N/NE direction trying to stay in the lighter parts of the woods and ultimately regaining path at the sella.
Red and white CAI signs up valley to a point (then perhaps going east). Red CAI signs on path that circles Don Marco. But not apparently continuing (unless it was the one damn path I didn't try).
Saw lots of strawberry trees in fruit.
Sprained ankle.