Robert E Graham Imagination is the essence of astral travel. Be that kid again and pretend again. Use ariel maps. Microsoft has a site of satellite maps of almost every spot on earth.
Most local libraries have free internet access.
Spend a few evenings looking at these maps. Get out some road maps and pretend you re driving on the roads the map pictures. Now get comfortable in your meditation position. Recliners are great for this exercise. If you have time go for a leisurely walk before you do this exercise.