Firstly, regardless of what you do you are going to have a massive training load while you are there, so you want a de-load period on either side of the trip. How we structure this is interesting.
I would continue on as normal. Start build on time, and do your intervals at the training camp. This will require a bit more discipline, as you will be doing 5 minute intervals up a 40 minute climb rather than just riding it as fast as you can but it would be more useful I think. Plus you can add tons of lower intensity work, and have a very nice high volume polarized week of training. Plus, if you stay on schedule the week you get back is a recovery week when you get back, so that is great timing.
The alternative is to extend SSB until the trip, take the week before as a recovery week, have a little 3 day recovery period at the start of next week and then train through the next couple of weeks with more SS. The reason being, is it is likely that what you will be doing there is a lot of long rides and SS work on the climbs, so I don’t see the point in starting build only to have it punctuated with a week of lower intensity work. Then take a couple of days easy when you get home and start build.