There pretty easy to replace. Some like removing the bed while others do the tank. I've done both. If the tank is empty it's not too bad of a job. If your straps are rusted, you might consider getting replacements to put back on. Worst part is getting junk in your eyes and still having 5 gallons of fuel still in the tank so it can be awkward to handle. Hoses had be difficult to unclip. This is why some pull the bed.
If you have a buddy or two to help lift the bed it's really easy to do. But I've done it by myself with some jacks and 2x4s. Roll the bed back over the rear wheels and tilt it up for room.
The ring that holds the sender can be rusted in and difficult to remove. May take some hammering to turn the ring and get it off. Make sure to clean up around it before pulling the sender so you don't drop a bunch of debris down into the tank
Otherwise it's pretty straightforward. On my uncle's gas truck, he's replaced the fuel pump so many times that he cut a hatch in the bed to gain access.
PS: i moved your thread to the fuel section