How to get from Peru to Bolivia to see Tiwanaku

We are looking to take a trip to Peru and the sacred valley. While there we would love to go and see the Sun Door in Bolivia. In reading it seems that it is a long way to get there and not easy as well as possible issues getting over the Bolivia border and back to Peru. Anyone have any suggestions on how we can accommodate this and is it worth the trip?

The distance depends on where you are coming from in Peru. This map shows the route to Tiahuanaco from Juliaca and Puno. The approximate travel time from Juliaca is approximately 4 hours and the distance is 234 km.