Garfield could have, and would have done the same thing with his evening, whether Jon was home or not. One might protest another problem with this joke about how Garfield's plans to cut loose without any authority figures around: not only does Garfield not respect the authority or find Jon much hindrance, but his goals are so mild. I don't have a problem with just this low key observation; eating junk food and watching TV all night is probably how a lot of us kick back and enjoy a night without the roommate/spouse/whatever,-it's-your-business.
The semi-joke is bolstered with slight, telling uneasiness when Garfield lovingly includes his food and electronics in a collective pronoun. There's also the implication that Garfield is using Jon's absence as an excuse for binging and being sedentary; telling himself he's only doing this because Jon's not here to stop him, as if he would behave differently otherwise.
The potentially awkward situation of a cat thinking silently to no one/the fourth wall but still setting up a joke with a visual reveal is cleverly handled with a contact-print style symmetrical layout. I can't really say the suspended thought bubble in an otherwise empty panel two exactly generates suspense for the punchline, but it's a nice layout. But yeah, it's mostly a strip about how fun it is to be home alone, even when you're just going to goof off in an unexciting way. That's actually kind of a nice observation that I don't see too often, so, uh, enjoy your "TV remote", Garfield. Do you plan to use it on the TV, or just eat cookies and look at it?