I travel quite a bit for business and run regularly when I'm on the road.  The key is blocking the time to do it in your schedule.  If you are doing C25K, just explain what you are doing to your family and tell them that it's important to you. 

The good thing about C25K is that it can easily be done on the treadmill.  I'd check ahead to see what kind of exercise equipment your hotel has and when it is available.  Many good hotels allow 24 hour access to their gyms, which makes it easier to squeeze in a workout.

You might also ask the front desk or the concierge if they can recommend any running routes.  A GPS watch is a good piece of equipment to have if you are traveling, since it can tell you exactly how far and how fast you ran, even if you don't know the area.  In a pinch, most models can help you navigate back to your starting point, if you get lost.

Here are a few posts that I wrote that might help you.  Have a great trip.

On the Road? Get a Handheld Running Route Map for Your Location

Traveling? How to Find More Handheld Running Route Maps

How to Run Safely in a Foreign Country

On the Road? Find a Running Trail and Explore!

How to Find a “Drinking Club with a Running Problem” Near You

+1 to what the previous posters mentioned - especially the point about blocking the time in your schedule. By the way, there is a big difference between being ABLE to run and being WILLING to run. If necessary, negotiate in advance with your family about a time for running that fits your schedule and family's schedule best - and do your best to stick to it. Just one caveat about timing: If you're using a hotel gym, they tend to be most crowded in the early morning (between about 6 AM and 7:30 AM). If you can't get on a treadmill because they're all taken and/or people are hogging them, get on an elliptical or other crosstraining equipment - whatever it takes to get your aerobic workout done.

I also travel a fair amount for business and ALWAYS bring my running gear with me. Often I have to put in 13 or 14 hour days on travel (like 8 AM till 10 PM, including lunch and dinner meetings) and blocking some time for running keeps me sane. For me it has to be in the early morning or it will not get done. As for running while on vacation, I will always bring workout gear, although whether I run depends on what other physical activities are in the plan. Often I do a lot of hiking or biking on vacation, in which case running can slide for a week. But if it's an otherwise sedentary vacation, then will definitely make the time to run.

I LOVE to run on vacation - it seems like the run goes faster when you aren't on your normal route. Even if you don't do as many runs as you would have that week at home, you'll be so proud of yourself for getting out there a couple of days. And it is a fun way to experience up close a bit of the atmosphere of the city you are visiting. If you don't have a Garmin, you can map out a course on MapMyRun or USATF web site. Or just carry your cell phone, run one direction for 15 minutes and turn around and head back. If you get up and out the door early enough, it shouldn't cut into your vacation day too much.

I just got back today from a cruise to Bermuda followed by a couple days in New York city. I ran in the gym on the ship, on the beach in Bermuda, and in central park in New York city. The last two were awsome. The beach was beautiful and I wish I could have ran longer but did't want to take too much time from my time with my wife. My run in the park was really a fun experience. Coming from a small town in Pa. I couldn't believe how many runners were out there at 6 am on a friday morning. I've run some local races that had less people. It is great that New Yorkers have such a great place to exercise. My point is to take advantage of chances to run in different places with different people. I find most times they are my best runs and I love meeting and talking to runners from other places. I always run when it takes the least time away from wife. After all it is her vacation too but compermise has worked for us for 27 years now. So take those running shoes with you and enjoy new experiences.

I have struggled with this as well. I always pack my workout gear. I try to be reasonable - and look at the reason for travel. If it's leisure, I tell myself working out should be a part of my leisure life and try to work out at least every other day. I was in San Diego earlier this year and the weather was just so beautiful that I had no trouble working out all but one day that I was there. The first day I had some time to kill, so as soon as I checked into the hotel, I immediately changed and found the gym and got in a run. The day I didn't work out was the last day, with packing and getting to the airport and saying goodbye to my friends, I didn't want to spend the time. Plus, I was hand-washing my running clothes and they needed time to dry before I packed them.

Recently I was in Tampa for a week for work. Spending 8 hours in training, I was tired every day and didn't push it. The hotel had no workout room and wasn't in a very good location for me to run alone outside before dark, so I did my best to visit the pool a couple of times and make wise food choices knowing I wasn't getting the calorie burn I typically do in a week.

I'll be going to Mexico leisurely soon, and I keep pondering this question. But it's leisurely and all inclusive, so my best bet is to get up early every day and just do it! Fortunately, I'm not a big drinker so I won't be taking in a bunch of alcoholic calories!

This is kind of silly but one thing I do when I travel is make all of my leisure/sightseeing/casual clothing the same as my workout gear. So, instead of khakis or jeans, I wear workout shirts, shorts, bra and pants, jacket, etc. Just being in this "sporty" look the whole time, I feel sporty and tend want to walk or move more than if I'm wearing stiff shoes or heels and dresses.  When I get back to the hotel, I have no reason not to head right to the gym or out for a run or walk. It doesn't always happen, but this is just my little mental thing I do to keep me in an active mode.

By the time I read your post, you've probably already gone on vacation and come back!  I am an airline pilot - if I didn't run when I traveled, I wouldn't run at all!! Most hotels offer a fitness center, or can point you in a direction to go outside where you won't be mugged.  All it takes is a little planning and getting your mind right. Surely you can set aside 30 minutes to go for a run? Good luck and keep up the good work.