It's not fun, I did a couple years back, luckily I was able to setup new tanks at the new house and let them run for a few days prior to the switch. I bagged all my fish and didn't lose a single one. All dwarf cichlids and tetras. Trick is matching water or taking old water with you, I brought a few 5 gal buckets. It's not practical but it's necessary if the parameters are far different.
Only moving a block away? that will be a piece of cake! I moved 9 miles once when I had 5 tanks... I simply put the fish in 5 gal buckets, along with about 50% of the water from the tanks... loaded the tank, fish and water... drove to the new place and set up the tank. its a little time consuming, but you should have no issues.
My longest move was about a 3.5-hour drive. Some of the fish went into buckets, most went into bags so I could control water quality a little better. All my Bettas went into the little cups that they use at chain fish stores. Bags of fish went into ice chests to help keep water from fluctuating too much, or styrofoam containers. I drained tanks down so that water barely covered the rocks, then loaded up my truck as quickly as possible and hit the road. I had about 10 tanks or so at the time, nothing huge. A big range of fish. Corys, Plecos, Bettas, Goldfish, Guppies, Red-Tailed Shark, Rainbow Shark, Angelfish, Columbian Shark, Pictus Cat, Danios, Bala Sharks, Tiger Barbs, etc etc etc...
I basically drove as quickly as I could, praying the whole way that my little wet friends would make it. Got to the new house, ignored all the crap that needed unpacked, and made a dash inside to set up my tanks. Made sure the water was the right temp and just added in water conditioner and hoped that the bacteria colony in my rocks and filters would get everything back to normal quickly. Didn't lose a single fish!