There are simply way to many variables to comment from afar. Walls have to be cut into sometimes, and other times you can put larger duct in the available space from one end, and then connect the far end.

Not enough information to go on, but I'd start with a guess of about $100 for materials (5 ft of 2" copper pipe plus fittings), depending on what your total length is. I'd expect labor to be close to double what you paid last time. Is there easy access to the entire run of drain pipe? Could you possibly wrap the PVC with sheet metal (aluminum flashing) and clamps. Rats/rodents cause other problems. What are you doing about the root issue? JM$.02W

You might want to prioritize what you can live with and what you absolutely have to change. When we moved we had a lot of repairs to do. I never was drawn to cherry cabinets or staggered cabinets--I strongly disliked them. We couldn't afford to redo them. So, I needed to figure out how to live with them. I went to work at houzz. I would type in cherry cabinets and keywords that describe my style. I would see what the experts did with staggered cherry cabinets and I got so many ideas. Now I don't have a problem with the cabinets because I merged them into my style and the "cherry ness" has disappeared. I only see my style now and before I only saw cherry. So, take a look at houzz and see what the experts have done with what you don't like about your kitchen and see if there is a way for you to work with it. I don't think you will regret it. A funny sidenote . . . I couldn't stand the granite and couldn't afford new countertops. We had redone the kitchen in our previous home 3 years ago and loved loved the granite. The only person that ever loved them as much as my husband and I was my sister. No one really commented on it (maybe they disappeared because of the other things going on?) The granite in my new house gets so many compliments. I guess I was wrong? The granite isn't as hideous as I thought? Apparently it is a good thing that I didn't spend a lot of money changing something that was perfectly good. I spent so many nights awake before we moved trying to figure out how I was going to live with cabinets and granite that I didn't choose. Instead I think I needed to work on accepting what I had and getting creative. And, also, be aware that in a empty kitchen many things that stand out will blend and even disappear after you add your style and decorate. Hopefully this helps. I don't want to see you spend a lot of money redoing a kitchen that you can make beautiful without breaking the bank.

rockybird, I hope everything will get resolved to your liking. As you know, I have been working on renovating my house. This being our first house and first reno, we have seemingly run into every possible obstacle. We just suffered a four month delay because the architect did not measure the existing house correctly. The approved plans for the existing part of the house have dimensions that are off by as much as 10". It wasn't just a few dimensions. There were mistakes every where. To make it worse, the incorrect dimensions were all larger than what they should be. This messed up all the windows and doors placements and the interior layouts. The GC told me he has to build what the plans said even though they are not correct, so I told him to stop working. Of course, the GC is not totally blameless. His sub poured the foundation for the addition one foot wider than what the plans specified. I went to my architect and went over all the problems and he said he would fix them, but he is super busy and I had already paid him in full since the plans were approved. It took over three months to get everything updated correctly. Once I had the updated plans, the GC is swamped and I had to wait a month for his guys to restart work at my house. Even now, things are still not in full swing as we are waiting for building materials. This has been such a crazy process! I am not sure I will ever want to tackle another renovation in the future if I can get this one done.