I think you're talking about the one in the attached link? We got a 7-bar version years ago and, I have to say, they're really good to use. Too bad we couldn't find another one. Here is a link that might be useful: IKEA towel holder

I assumed you had central air conditioning. If you are going to have a window unit in the kitchen, then that effectively is a separate zone. You should be fine in the summer assuming the window unit can keep up with the heat gain of the kitchen. One window unit in such a large space may not be able to keep the temperature even throughout the whole kitchen when the sun is beating down on the windows. Think about two smaller units installed at opposite ends of the room. It is difficult to say if kitchen will have the same temperature as the rest of the house during the winter. It is better insulated, but it has a lot of windows and a high ceiling. It will be probably fine during the day, but may be cold during the night. How many feet of baseboard will be installed? To what temperature do you set the thermostat during the day and night? If you don't want to spend the money now, then I suggest install the new plumbing for the baseboard so that it will be easy to zone in the future in case you are not happy with the temperature of the kitchen. I would also run the wires for the thermostat now in order to make it easier in the future. Thermostat wiring is inexpensive and simple to install when the studs are exposed.

I doubt that you would be so lucky as to avoiding the rebar. Without the benefit of those determinations, $3-5k would not be an unreasonable expectation. Engineering is an "exact" science, based upon "assumptions," which the local building dept. may deem you a beneficiary of, or not. It's how it works. Your roof and ceiling structure will determine the cost of a skylite installation. Potentially a substantial reduction in cost.

Well I hope to some day enclose half of the front porch. I will need to figure a way for cooling. There is no way to plant in front as we are too close to the street. I would like to enclose the right side of the porch, as you face our house, which would cover the front door opening into between our dinning room living room space. This would make an air space in winter to help keep cold air blasting into the house when we enter. Leave the other side open for a landing on raining or snowing days while standing at the door letting us in. Would also create that sunny winter spot you are trying to create at your house for us. :^))). I need to find some sun blocking or heat stopping kind of shades for windows before I even consider enclosing this end. Maybe special insulation in the walls too. It is a project down the road. We always considered when we had the porch built on the house to begin with. Since it is all on a regular foundation like the house and actually is part of the house we just need to close it in. There are no permits needed unless we decide to do some special electrical. There is already a plug and a light. So a some day project. I know I would use it as I am using it now in the evenings. Here is a link that might be useful: Re-Arranged the front porch.