Get a barrel where the whole top is removable and just dip the water out with a bucket. You have to be able to clean your barrel as the water coming off your roof will likely be very dirty, especially for the first few minutes of the storm until the rain washes all the dust off your roof. If you don't clean your barrel after every storm eventually the bottom will be full of mud from the dust on your roof.

Or turn the barrel on it's side and put an elbow fitting in the larger bung hole, then install a faucet in the smaller hole.

You'll get tired of that hand pump real fast.
The drill pump isn't worth the $ because you'll have to replace the drill too often. They aren't made for sustained use. A small pond pump could be dropped inside the barrel. Just make sure the cord is long enough. I would turn the barrel on it's side or even better upside down, put a fitting and a 90* degree pvc elbow with a nozzle on one of the caps and cut a hole in what was the bottom to fill it. Check out the link below for a similar design. This can be done with one barrel.

Here is a link that might be useful: MNT's Rainwater Collection System with Manifold