The principal value of altitude training comes from breathing there, not training there. You may have heard the rule “sleep high, train low”. That is still the current thinking. Staying at 7500 feet overnight during your trip is the “altitude-training”.
Riding hard at altitude is pretty much a waste of effort for someone who wants to perform at sea level. The reason is simple: At high altitude when you go “tempo effort” you’ll be producing power similar to what you produce at an endurance effort at lower altitude. Individual muscle fibres only become trained if they are recruited repeatedly during training, and at altitude fewer fibres are recruited so there is less training effect.
Take the first few days at altitude easy until you get over the initial adjustment on the third or fourth day. Then there are three choices what to do. If the area you’ll be riding has no easy access to lower than 6,000 feet, just load on the miles at an endurance heart rate (70-80% of max) after the first few days.
Going harder at altitude is more fatiguing than going harder lower down, and recovery takes much longer. If you have access to lower altitude (under 6,000 feet) and want the optimal physiological effect, go as low as you can to train and return to 7,500 feet to sleep. In that case, you could maintain your normal training.
Finally, option three is to admit that you just want to ride those giant mountains, enjoy the roads and views at whatever pace is comfortable, and then recover when you get home.
Note: If you train by power, don’t use your normal zones at altitude. Your power at any given heart rate will be reduced and sticking in normal zones will dig you a big hole in three weeks. Either retest at altitude after a week of adjustment and set up new zones, or just calibrate your power output by your heart rate – that is, use the heart rates you ride at home when riding in your power zones and ride whatever power those turn out to correspond to at altitude. The first few days the power will be very low, then it will start to come up rapidly but not as high as at home.