I have done quite a few. My choice would be a good fiberglass base, unless you like being on your hands and knees cleaning soap scum out of grout. Use the right grout, unsanded for up to 1/8 " grout lines and sanded for the rest. I use a latex additive instead of water for mixing grout. makes it about as water proof as you can get. You are not going to be perfect because most tile are plus on minus 1/16 and after a few rows it adds up. I mainly use home depot for my tile needs because you can take back what you don't use. Most high end tile places what you order is what you pay for and no returns. Start in middle of long back wall and work out, end walls start on the outside and work in using a bullnose tile for your first tile. I usually lay the first row of tile the day before, so you have a good solid base to work off from. I also use the premixed cement for the tile because that way I can stop and start when ever I want, and for first timers that's a good thing. Rent a good tile saw. It will make things so much better. Check out some of the internet vidios, some are pretty good. If you get into trouble pm me and I will see if I can talk you through it.
This is all good information. I have done many, many tile showers.
First on the base- yes, a tile floor can be a PITA to clean. But, tile certainly looks better. A fiberglass base will definitely save you time and money compared to a Schluter base. But if you choose to tile it the Schluter base and especially the drain are the way to go for sure. If you use their base the slope is set and as long as you choose a good small pattern mosaic drainage is perfect.
The Schluter Kerdi is the best waterproofing membrane out there. First time use can be a challenge to say the least. First, use the trowel they recommend. Second, mix your thinset a touch wet. Dry thinset will not allow the Kerdi to bond and is very frustrating. For seams I recommend butting the joints and use Kerdi band to seal the joint rather than overlap because you create less of a hump in the wall. Just make sure you do this part right, it is the most important part of the shower base and walls.
Regarding the framing and sheetrock you are going over, make sure everything is flat and straight. If you pick large format tiles it doesn't take much of a hump or dip in the wall to cause you serious trouble. Even the sheetrock tapered joint can be a challenge. If possible, have everything flat and square in all corners. It will save you a ton of headaches.
Think through your tile layout and draw it on the wall if needed. Remember cutting holes for shower valves, heads, and mounting niches can be a challenge depending on location. Try to get everything planned before you begin. Niches need to be waterproofed with Kerdi or you can buy the pre-built ones.
I too like to set one row of tile and let it set overnight so I have a solid base to build on. Then, go up the next day. Get good tile spacers that stay in place, the ones that can be used multiple ways are best. Stay away from the cheap X style ones.
Remember to mix your thinset a bit on the tight side for less mess. You will get it everywhere anyway your first time. I pretty much exclusively back-butter the tiles rather than place thinset on the walls. Much cleaner.
You will learn tiles are far from square and constant adjustment. Get a pack of tile shims to help. And, keeping the tiles flat is a challenge. Keep your thinset amount on the tiles and wall consistent. Add/remove small amounts of thinset if needed to maintain a flat tile surface.
A good tile saw is a must. A grinder with diamond blade and a drill with tile bit helps too.
I only use premixed grout anymore. It is much, much better than dry mix grout. Color consistency with dry mix grout is completely dependent on how much water you put in and batch to batch consistency can be difficult. With the premixed that isn't an issue and it is completely waterproof. Just do not do too much at a time, a couple sq. ft. then clean up that area.
I always but from the tile store but don't know where else you can get the materials. A home center allows returns so that is nice, most flooring/tile stores don't.
I hope this helps, let me know if you have questions. BTW for a 42" x 60" shower I would plan on spending a solid week on it from start to finish.