Great question Amy! That said, here is the general rule. No more than 2 days of longer and/or harder without a recovery day. A recovery day can be a swim workout, easy spin or a day off. Just the thought of ‘stacking’ workouts gives me pause.
That said, if you are smart about it, you can probably get most of them in. Just be sure that you are moving them around so that you are getting in a recovery day during your 3-4 back to back days. It’s hard to give exact details here because I don’t know specifics. However I can say that doing double workouts on a couple of days shouldn’t be too bad as long as you are also prioritizing as much sleep as possible and doubling them up appropriately following the rule.
Finally, always remember your prioritized workouts each week…your longer swim, your long bike and long run. If you can get them in, you can always get back on track after your travel. Hope this helps!