Pictures would help. But generally the countertop is flush and the gap fairly small between counter and top of the range so things can't fall down between. If the cabinets but up against the range, this means the sides of the counter are flush with the cabinets. If the cabinets have a gap, you use fillers to close the gap but the counter still comes up very close to the sides of the range top, overhanging the cabinet and flush with the filler.

Yes, I am aware that all ranges are not created equal, but I certainly don't want to build this kitchen around a 10 YO range! I just want to be sure I can change it out when it dies and not have to move any cabinets/counters to make a new one fit.

I have found some older posts and other articles about this and it seems like (a) most prefer a tiny counter overhang on the sides and (b) most "standard" ranges are slightly less than 30" to allow for them to fit in a 30" opening. So right now I am planning on 30-1/8 to 30-1/4 between the cabinets on either side. Many of the ranges I see on AJ Madison are 29-7/8 and specs indicate they are designed to fit in a 30" opening.

I won't worry about the uppers lining up exactly - my concerns was due to a framed doorway at the end of the run on one end and it seems like I will either have to have a sliver of wall showing where the base cabinets are unless I put a side panel on the base side next to the door which is a waste of money IMO. Or lose the door trim entirely and just do a sheet rock opening which would allow for a wider door opening anyway.

Yes, live-wire I am trying very hard to check, check, and check again to avoid problems! The Ikea planner seems to err on the side of conservatism where the range is concerned! The over range fan cabinet is 30" but you need side panels on the side of each adjoining wall cabinet, so for the base cabinets to line up "exactly" you would need a 31 inch opening. 1/2 inch on each side of the range seems like too much of a gap and a great place for dirt to collect! I don't want to feel like I have to add a filler there.

You should be able to find the specs online even for a ten year old range.

If you don't add filler next to a wall, drawers won't clear door casings. If you don't add cover panel on either side of the range, the opening will be much too large, and you won't have the hood centered on the range.

Sophie, I'm not quite sure where the comment about filler next to a wall came from, but yes I am aware of that - 2" is minimum and I have more than that in all the right places! But your comment about the cover panels has me wondering - if I do the cover panels on the base cabinets to exactly correspond/align with the cover panels on the wall cabinets on either side of the range hood above - and the 30" range hood cabinet goes between them, then how can I have anything other than exactly 30" for the range opening? So it doesn't matter what the specs for my existing 10 YO range (or any other range I may ultimately replace it with) call for. That gives 1/8 inch to spare for a (somewhat standard) 29-7/8" range and any counter overhang is essentially impossible! Am I overthinking this?????

There is a similar dilemma for the refrigerator opening. In my primary home kitchen - which was done about 5 years ago using a cabinet designer, the refrigerator opening is 36" exactly. Its so tight that we had a heck of a time getting the unit perfectly level so it would fit in the opening. It actually touches the wood side panel in one spot. On this remodel, I'm happy to have an alcove for the refrigerator so that I don't need to worry about that. I'm using a side panel/filler on the over refrigerator cabinet where it meets the alcove side wall - not going down to the floor. That will give me an extra 1/2" of space so we won't need a shoehorn to get the refrigerator in and out! Maybe it will look a bit unbalanced without the full height side panel on one side but not sure anyone will notice....

And yes, I know the refrigerator door and gasket will have to sick out beyond the alcove in order for us to be able to open the door.

Base cabinets installed level, plumb and on plane to each other are critical for a proper appliance fit. You can have 30" at the top, 30" at the bottom, but if it's a parallelogram, the stove ain't goin' in.

I got a callback on this once. Guy insisted the stove wouldn't go in the opening I'd left and he was right. My opening was square and with the feet on the range out of adjustment, he was trying to insert a parallelogram into it. I didn't charge for that, but I should have.

^Exactly. You have to think in 6 dimensions at all times when designing, or installing. You mentioned cabinets against a door frame. Not everyone remembers that trimwork has depth to be accounted for.