Don't quite understand what your need/want is. You do not need a printer connected and you do not need to resize the photo in order to print it. In the Lightroom print module top right of the photo screen there's a create saved print you can create one then print it when you get home. when you click on the print module all the print settings come up on the right hand side scroll down to the bottom click on the custom file dimensions and just input the size you want to print if it's not the exact ratio as your photo you'll have to crop your photo or lose part of it. Up a little farther is cell size you can change that to the same size as your print for borderless or you can change it to show a border and the print you have selected in the view window will show you what you get. If this does not help please explain more detail what you want to do.