Taking your Practice on the road doesn't mean you have to sacrifice your workout. Why not pack some props in your suitcase to keep your workout going.
If you are taking a beach vacation, why not pack a mat and practice on the sand. Manduka is my absolute favorite mat provider. Eco friendly, thick, slip-resistant, recyclable. They also carry towel like mats which are super easy to pack, wash, and wipe the sweat off with when you're done. Thick enough to roll your spine on for Pilates. Non-slippery for even the hottest of yoga practices. These mats are well worth the investment and my mat of choice for life.
Resistance bands are super easy to pack and use wherever you are. They come in various resistance and options. I like Thera-bands. Use them for arm work and leg work, on your own or hooked onto a desk, bed or door in your hotel. Tubing with handles or without and/or Exercise Bands (I prefer latex free). These can help take your matwork to the next level and mimic exercises done on the Cadillac and Reformer. STOTT Pilates has many DVDs using resistance bands to choose from or have an instructor lay down a personally tailored workout for you to download onto your mobile like pi-LALA-tes : Pilates without Borders (Insert shameless plug here).
Magic Circles are a great small prop as well. A little more awkward, heavy, and space consuming than the resistance bands. Gaiam has a lightweight circle that comes with a DVD. Children's playground balls can also substitute for a ring and can be found in any toy store, target, and even some grocery stores (depending on time of the year).
These are just a few suggestions to take your practice on the go. You really don't need much to get a great workout wherever your life may take you.