2 x 23kg allowance The only problem is getting it back to Scotland then, you will likely have to pay for that extra bag. What we have done in the past is just packed a box in the US and brought it back through, so only paying for the one way.
Have a look at going through Stockholm Arlanda as its an extremely managable airport, but it will add on some time/cost/hassle. There are two hotels in the terminal, with excellent prices for weekends (otherwise pricey during the week). We roll in, check in, head up to bed and roll right out into flight check in the next morning. Given how the flight is timed it makes sense, but you wouldnt necessarily need to do the same on the way back as LA lands early enough.
This works pretty well from the London area, but Scotland you will have to go to Edinburgh first and then there is one non-stop a day. Some people don't mind the extra hassle/cost and some people do - just comes down to personal preferences. Looking at some of the other options, Aer Lingus is probably the best bet to transfer in Dublin, otherwise its LHR all the way. Sure its a big airport but it has efficient flow and plenty of space in T5 , I dont get the hate for it? Any other major connection in Europe is going to be just as bad, if not worse (AMS, CDG, FRA, MAD) and I avoid the NYC area. Besides, if you transfer in Europe then you are protected by EU law in terms of delay and could receive compensation, in the US you are at the mercy of the airlines.
Yeah, we've been through LHR many times (and Gatwick once) and there has almost always been a problem for us there. A couple of times it was a royal nightmare. (They left the Daughter waiting for an hour for a wheelchair, sitting outside the aircraft door, during a connection the last time she flew alone.) So we don't go through LHR.
I like the EU law thing, and would prefer to have a direct flight once we are out of Scotland, from wherever in the EU we have to reboard. I remember one return trip (and I don't remember which airline it was) landing in Detroit and having to get our bags and go through customs and then put our bags back on the conveyor to be re-loaded onto an ongoing flight with the same airline. So I either want flights that are direct or ones where we do not deplane if we do have to land in the States at somewhere other than our final destination. Want the bags checked through to LAX.
We are planning to put carry-ons in our checked bags going over and carry a change of clothes in our "purses", as we have things we need to bring back from the States. I was not aware that you can have a box count as luggage - that would solve many problems.
I'll check with the airline, when we choose one, as to what they require. We didn't want to have to purchase another suitcase over there - we have too many as it is. The Daughter left several items of clothing behind when we moved that she wanted to bring back. (They are stashed in a friend's garage.) A big box should do it, when added to the space in her carry-on and suitcase.
We need to go on-the-cheap, pretty much, so I think Stockholm is going to be out. I did find a flight GLA-LAX that went through Amsterdam with a two+ hour layover, and then direct to LAX in our price range. (Coming back the layover is longer, but we won't really care at that point.) Going to EDI doesn't add much cost - the bus over is free for me and the Daughter's fare isn't too high, if we have to leave from EDI.
Next question - UK credit cards. I just checked my UK Mastercard (rewards from RBS) and it has foreign transaction fees on it. I can switch to their other card, which does not offer rewards and does not have foreign transaction fees, but thought I might like to see about a second UK card. Just for when we travel. Can anyone recommend one? I have done a little checking, and the PO and Halifax have some basic travel cards. I wonder if I should check for an airline card (if they have those here)?