Well, there are a few different approaches.
You certainly can use the xmp sidecar approach. They won't have certain catalog settings stored in them (such as collections and some other things), but it can be a painless approach -- you can copy the folders onto your desktop, do an Import from files and folders, select all the imported files, then carry out a Read Metadata from files. And your done.
Another approach is more Catalog-oriented -- you can select the folders/images that you want to bring into the desktop. Then in the laptop you can do a Export to Catalog from the File menu. Locate/create the new catalog, keeping the catalog and the files into a "neatly close" location. Then, copy both the images and the catalog folder over. You may want to check by opening the new catalog in your desktop -- it may have a hard time locating the images and it would be good to right away right click on some top-level folders and choose to Find missing files/folders so the catalog will have good integrity. Then open the desktop catalog and you can perform an Import from Catalog operation, browse to the new catalog, and select the folder(s) and perform the Import. This should get all catalog metadata imported, although I know it's more complicated.
Alternatively you can just copy the entire catalog and images onto the desktop assuming all your "stuff" is to be imported, go ahead do that integrity/Find check, then just do the Import from Catalog on the whole batch.
Hope this help a bit. People can get confused with these operations -- make sure you have made successful operations before you delete anything you think you are "through with"!
