I love taking a break from home working and hitting a coffee shop. For me, it's just a way to improve my mood. Similarly, I'll break out the lawn chair and sit outside to work -- that is just as effective emotionally, but not quite as practical (glare, no real table, etc.)
My only gripe with coffee shops is the bathroom break. No way am I leaving a $2000 laptop on a desk unattended, but after a few cups of anything, you have to go. Sometimes I'll ask someone to watch it for me, but if there's no one who's around consistently or who seems trustworthy, this can't always work. So I end up packing up my shit then unpacking it again...
I guess it depends on the kind of place in which you work, but I leave mine (screen locked) at my table all the time.
Alternatively: get a lighter laptop and set it so you can close it without putting it to sleep; then you can take it with you easily. You don't need to pack everything up; the resale value of an unattended power adapter is quite low.
My only gripe with coffee shops is the bathroom break. No way am I leaving a $2000 laptop on a desk unattended, but after a few cups of anything, you have to go. Sometimes I'll ask someone to watch it for me, but if there's no one who's around consistently or who seems trustworthy, this can't always work. So I end up packing up my shit then unpacking it again...