Looking at making a new veranda with a cold room underneath and extending the roof to cover the area. The new veranda will run the width of the house and extend out about 4 feet. I do not know how to design the roof extension and would appreciate any help from those who have the knowledge and/or experience in this matter. See photos for a visual display.

Your answer is shown in the picture on the lower right.

But I am not sure how it was achieved, is the existing porch gable roof to be demolished, and tie into the existing trusses of the living room gable roof? Is that the only way of doing it?

Well, if you're gonna have a veranda across the front of the house, the existing porch kinda hasta go, doesn't it?

Then you would frame rafters from the face of the existing gable end, down to a beam across the front of the verand, which is carried by the columns. At the ends, you frame a small hip, and frame jack rafters extending left and right, in almost the same plane as the roof you're tieing into.

If the existing roof is really framed with trusses, you don't touch them at all. You don't add load to them, or certainly absolutely don't cut them. However, I doubt that it is framed with trusses...it more than likely has conventional rafters.

There are enough tricky little issues with what you plan that an investment in architectural services would pay for itself. Have someone who knows what he or she is doing design it, and then just do what they say.

What would be involved if one were to use the extending large gable as an alternative and remove the one above the porch?

Then you would need beams at the ends of the porch, carrying rafters and ceiling joists running parallel with the front of the house. You would have to ensure that there is something in the existing front wall to carry the ends of the beams there, and that there is a complete load path from there to the earth. The outer ends of the beam would be carried on the porch columns, and again, a complete load path is required.

Just to explore another option what do you think of building a new gable to cover the veranda/porch, would it be best to have it as the large one is, that is to the left, centered, or maybe to the right? Should it be as large as the existing one or smaller in size?

If you simply extend the frontmost gable, it is a relatively easy roof, but it won't cover the entire width of the house. Anything else gets more complicated and presents a few tricky roof intersections to design. The photo on the lower right shows the best way, in my opinion, to cover the full width of the house. Your best bet is to find a good architect to advise you. Whatever you pay him or her, you'll save a couple of times over compared to proceeding without proper structure and all the roof intersections worked out for you.

Example: look at the post "Sagging Garage Door Header" in "Framing"...that poor guy is facing a $15,000 bill to repair an error caused in part by his failing to retain an architect to design his garage. He might have paid an architect $1,000 to design it. Did he save any money?