If you have a router with a 1/4-in. collet, buy a carbide straight-cutting bit with a 1 to 1-1/4-in. cutting length (sold at home centers and woodworking stores). Place your straightedge on top of the board you're jointing. Set the straightedge guide back on the board so you remove only 1/16 in. of stock at a time. This technique is easier if your router has a base with a straight edge, but it also works with a round base. This “straight edge on top” method works best for 1/4-in. shank router bits because it puts most of the force on the router base instead of the bit's shank.
If you have a router with a 1/2-in. collet, go with the “straight edge on bottom” method by using a 1 to 1-1/2-in. carbide flush trim bit with bottom bearing (sold at woodworking stores). This technique puts the force on the bit's shank, but that's OK with these heavier bits. Just tightly clamp your straightedge on the bottom of the stock and set it about 1/16 in. back from the stock's edge. The only measuring you need to do is to make sure your board winds up with the same width on both ends.
You can use a router to make those square, straight edges you need to join boards into a solid wood panel. It's more time-consuming than using a jointer, especially for long boards, but in some ways a router works even better. You don't have to worry about having a long enough outfeed table (or workshop) for long boards or having the infeed and outfeed tables perfectly aligned. All you need is a good carbide straight-cutting router bit and a piece of 1/2-in. medium-density fiberboard (MDF) with a factory straight edge. The photos show two ways to make your joint.
If you have a very bowed board, snap a straight line with your chalk box, then use your circular saw to get a rough straightedge before routing.