There are two daily busses travelling from Sta Cruz to Asuncion. The journey takes about 32 hours and costs 50 USD. After the border in the Paraguayan Chaco the road turns into a bumpy and dusty track. It takes about 10 hours from the border to Mariscal Estigarribia where the road starts being paved again. Before continuing the journey a severe drug check is taking place which lasts at least an hour. The following passport check takes another 45 minutes.
ParaguayParaguay is not a country for sight-seeing. Full stop. Asuncion might be a fine place to stay for a while, if you want to learn the language (Spanish rather than Guarani) and meet friendly people.
Jesus and TrinidadIs a UNESCO World Cultural Heritage site and as such worth a visit. It's actually two sites which can be visited in a daytrip. There's no organized tours, so you have to take a bus from Encarnacion. Ask the driver if he can drop you at Trinidad. There's a restaurant and a shop at the road where you can ask for the road to the site. It's about a 10 minutes walk. Jesus is about 12 km off the paved road. There's a taxi driver waiting at the junction a hundred meters further the road near the gaz station. Car and driver are not looking very trustworthy but you will survive.
UruguayIs a seaside destination.
MontevideoIf you are there, don't miss lunch at the port market (Mercado del Puerto). There I had one of my best steaks ever and the ambience is just stunning.
Punta del EsteIs a first class seaside resort. Stay at hotel Residencial 32. A single room with bath costs 20 USD. The place is very clean and friendly. A substantial breakfast is served. It's situated next to the bus station and five minutes walk to either beach.
Buenos AiresTry to be there on a Sunday and go to the flea market in San Telmo. There's nothing comparable.
Travelling by BusTravelling by bus in South America can be a real pleasure. Travel with Cata in 'coche cama' from Buenos Aires to Mendoza. The seats are of long-haul flight business class quality. You get food, wine and whisky. Pillows and blankets are distributed aswell.
Hiking in Aconcagua provincial parkIf you are off season, just forget it. You will be on your own, have to organize mules. Camps are not staffed.
MendozaA good base for excursions. The city itself is friendly but has absolutly nothing for sightseeing.
Road blocks in BoliviaIn many Andean countries like Bolivia or Ecuador people use to block roads in order to express their social dissatisfaction. These activities might be anounced or might not. Stay tuned and consult the internet at times of political unrest.