I’ve tried a couple of variations of all these options. What i have found to be the best balance (for me anyway) between keeping an enjoyable level of activity, maintaining fitness and also making time and allowances for other priorities is to completely hit pause on whatever training i’m doing and turn the vacation into a mini training camp for something else, some other element of athleticism. Like i’ll use the rowing machine, do a bodyweight circuit with burpees, do yoga, stretching, core, strength, running. I pick modalities, workouts and timing bsed on what works best for me during that week based on my time available, recovery time and available equipment, not necessarily what’s the best “substitute” for a planned workout. E.g., trying to replicate Cobbler on my parents’ 1980s exercise bike would be miserable, but doing 30/30s followed by sets of burpees is not bad at all.
Tl;Dr, trying to follow a plan religiously but with substitutes during travel has never worked with me, but hitting pause on the plan and doing my own thing for a week or two has, and it doesn’t take that long to get back up to speed when you get back, especially when the racing season is still so many months away.