Jardin is a city in Colombia.
North towards Medellin
Just go at the gas station at the end of the village. It shouldn't take you more than 5 minutes to get a ride.
There is indeed a road going up the mountain that goes directly South to Riosucio. But you need to know that this is a very muddy road which takes around 3 hours for 50kms. Not many cars pass through, but the few cars that pass will nearly 100% stop. In Riosucio, you reach again the highway and normal roads
Accommodation and Sleep
Two streets from the central place, there is a path that goes down to the river. Over there is a very nice wild camping place. You have spaces for tents and hammock, and water from the river. You can also probably make a campfire. Nobody comes here at night and it is safe. Just some hikers in the morning.