No, You have to set it up as Dual Boot, to tell the drive (or OS) which version to load upon start up.
With the same OS, it should be pretty easy. Goggle "Dual Boot Windows," and you'll need something like EasyBCD to set up the MBR for Dual Boot. It's alot of reading, but may be worth it, for what you want.
I assume you want to take some files with you on your travels, so why don't you get an external hard drive instead.
Although the files you'll use when in the desktop are still there, I'd be easier to sync up the desktop to the external, then to the laptop, with the software that comes with the drive.
If not, you'd want to partion up the SSD with 3 partitions:
1- Desktop OS
2- Laptop OS
3- Data/Media files
Depending on the size of your files, you may need a large SSD.
P.S. The external drive would be easier than pulling a drive to and fro.