I want to get Lightroom 5 off of my HD and get it on an external drive to free up space. I want to work exclusively on the external drive. After working on my pics for a couple months, I will be traveling to another home which has a mac so I need to import what I have been working on to the external drive at that home. Please advise how I need to do this.
You could select the master folder and "Export as a Catalog" to create a catalog copy, including image files, on the external drive.
OR copy your Image folders to the external, keeping the exact same folder structure, and copy the Lightroom Catalog folders also. Restart LR by opening the .LRCAT file in its new location on the external drive.
Great info at this link-
The Lightroom program however must reside on an internal Drive, so will need to be installed on the remote computer. You are allowed to have two installations (using only one at any time). You will need the Install file and the Serial Key.
(If your Serial Key is for an 'Update' version, you will also need the Serial Key for any previous 'Full' version purchased.