In reply to Gile5:
Agree with what others have said. For stamina I usually try and mix up a combination of
(i) roped 4x4s on sustained mildly overhung routes (2mins betweens reps, 15' between sets, roughly at a grade corresponding to your consistent onsight limit, perhaps 6c to start with aiming for 7a)
(ii) UDU (up-down-up) to replicate the longer time/mileage on outdoor routes; often the down is at done an easier grade but it trains recovery I think
(iii) continuous climbing 20 - 30 mins (either roped up and down - ideal but hard to find partner - or traversing); good on a recovery day and gets a surprising sweat on, much lower grade than the other two sessions ... like F5+ or F6a
I'd usually do one each of these in a week.
Another suggestion is to do at least one day a week of redpointing a coupe of grades above your onsight limit, perhaps picking 2 different styles of route. I can usually only manage 3-4 decent burns at this, thus it combines well with a warm-down doing (iii) above. Good for tactics, falling practise, and specificity to what I personally hope to achieve on a trip.
If you've been doing a lot of bouldering your lead head may have got a bit weaker (unless it's already very solid), and deliberate fall practise can be well worthwhile ahead of the trip. If you don't want to do this, then it probably means you need to ... jumping off the top without clipping the loweroff for your first 3 warmup routes takes seconds.
Worth thinking about your goals on the trip: is it to onsight lots of routes at your current limit, or to redpoint a few harder ones that are at a new level? If it's the latter, doing more redpointing indoors makes sense. Of course the stamina training is always good as it means you can simply do more in total
Good luck, wishing you a fantastic trip! Andy