I would like to chime in again in response to hollysprings' post. I do appreciate her insight, and others who are way more knowledgeable about this stuff than I. I agree that there are often circumstances that we may not be aware of that drive costs up, but let's face it, for many of us the construction industry is an enigma and it is already so hard to sift the wheat from the chaff. It only makes it harder for us when they don't let us know what goes into an estimate and we are left in the dark. Not only trying to find someone upstanding, but also someone who you get along with and understands your goals in the project. And I do think we should know the separation of labor and materials at least in some basic context. Obviously there is some range of cost that they have taken into account in order to come up with a lump sum estimate in the first place. Not to mention their own magic number that they need in order to make a decent living. And yes, there is a difference between nit-picking and getting a range of expected customer's choice driven costs. Shouldn't there be some responsibility on the contractor to let us know what types of allowances they are taking into consideration? I am new to remodeling, much like the OP. Unfortunately there are not many good resources for us noobs to educate ourselves about the construction process, how contractors work, good design, and product knowledge. Which is why I and so many others are on online forums such as this. I have been burned a few times attempting to learn and ask those same questions, like what the driving force is behind estimates and it is very frustrating because many contractors are not able to really articulate these things. What I have experienced is either a well organized design/ hold firm that does high quality work but only wants to work with luxury finishes or small time guys who come recommended by friends and neighbors that don't have a broad range of knowledge of products/design. And then those who do really great jobs for their friends and families but slack off for those who aren't on their Christmas list. No one I have met as a potential or actual client has been particularly interested in answering my questions, except with a short answer and a 'trust me I know what I'm doing'. I do know you get what you pay for and I am able to pay for what I want, but I also want to gain an understanding in what those driving forces are behind the costs. And in my expensive area of the country, it is very easy for me to feel and actually be price gouged.

Depending on the geographic area, the complexity of the job, on new construction somewhere between $5000-9000. If in existing building, maybe additional $3000-5000. I am using Payne as a price basis. Payne is a Carrier brand. Carrier is more expensive but not more than 20%. I did 80% install earlier this year with used equipment. It was less than $1500 total. It was a 2 1/2-day job, with new lines, rework to gas line, added 2 vents, new exhaust thru roof. Built custom plenum. All in all, it was only 2 1/2 days. I am fat, old and slow. Under better conditions I should have completed the job in a day. $20k is a lot of install for a 3.5 ton system. 5 tons sounds like Pheonix or Florida. Your contractor did not do a man J in all probablilty.

There are lots of durable and functional cabinets out there. I looked at and liked Cliq Studios, if you want framed. Your existing cabs are a fairly common design, should be easy to find something very close. I agree you should start out at Home Depot or Lowe's. You may find just what you want in your budget. For your countertop, you should be able to come up with a sq. ft. amount of counter space, then you can compare prices per sq.ft. Home Depot has an online countertop calculator to estimate countertops, using their selection of materials and prices. I found it very useful. Be careful that a 25" wide countertop doesn't block your doorway even more, leave plenty of room to get around the counter and through the door. I personally wouldn't like the look of mixing acrylic backsplash with quartz. As to granite, I have been told that there is more permanent type sealer available now, doesn't need redoing every year. And, at least in my area, it can be very economical, far less than any acrylic (a limited choice of stone at that low end, though)

Why cut the pipe? You can just unscrew it and get a correct length of pipe to replace it. If your dad has experience with gas piping he should know about cutting and threading black pipe on the job.