IPad maps: hide location circle

Maps in iOS 6 should actually do a better job of this, because it uses vector based maps, which use far less data than the old image-based tiles, which means they can stay in memory longer, and more can be cached.

You can test this yourself by loading up Maps for an area, then turning on Airplane Mode and browsing around. In my own testing I found I could keep maps for most of Toronto, although when zooming down, it lacked street names for some of the smallest streets.

Searching or routing won't work without a connection, but any route or places you searched for prior to disconnecting should stay in place as long as you don't clear them.

Perhaps I am misunderstanding the question. But why not just take a photo of the location you want to tag. This will (unless you have turned off location services for the camera app) record the GPS information. You can then create an album with your tagged photos and view them in a map view on your phone

If you export the photos you can extract the GPS info using various tools (if you are on a Mac you can simply do a "Get info" on the picture to find the GPS location. If you want to automatise the process you could use a tool like Exiftool.

Other possibilities are to get iPhone apps such as MapPocket, where you can pre-download maps of the area you want to go (Also ideal for holidays abroad, to avoid roaming costs) and then view your location on the map.