Okay confession time: I kinda like going to races by myself. There I said it!
The reason I like it is that I can do my thing on my schedule to make sure I have the best race experience. But keep in mind that I never did a marathon just for "fun" (well that is not exactly true) so I took them pretty seriously. One example of what frustrates me about traveling with others: I hate sitting around with a group of people deciding on where to go for dinner for instance. Now I have traveled with groups that I have helped to organize in which case I will find a place and just say "This is where we are going". At times people like avoiding the decision-making hassle of the crowd.
But let's say you are more social than I am or you are the person is taking charge of planning. So my experience lies in planning trips to races such as Hood to Coast where I was the team captain or a trip to Austin, TX for what was then the Motorola Marathon.
First, just how much planning is going to be centralized? For Hood to Coast one year we needed everyone to arrive in a reasonable window of time since we were driving to Seaside (the finish) and had rental vans for the race. So while I did not plan everyone's travel, I did ask for a time frame. For the Austin Marathon we set up the hotel and then each person was on his/her own to get to the hotel.
If you are going to plan the hotel get an idea of budget or if someone might want to use points. At one point if I planned the hotel we were staying at a Marriott property. Why? Well I stayed there for work and love Marriott (I am now open to Hilton as well). Then discuss where you want to stay like near the start/finish or near the expo or in the cool part of town with a lot to do.
Another option is to just let everyone choose their own place but plan on meeting spots. But honestly if I am traveling with a group, everyone staying in the same place is kind of fun. In fact something like AirBnB might be a better option for multiple bedrooms and a common living space.
Let's say everyone agrees to stay at the same hotel or at least ones close by. Then you are going to need to decide on places to eat. If I am organizing the group, I ask each person for preferences. Italian for distance runners is a pretty safe bet. I will start checking Yelp or my United Mileage Dining app for hotels nearby. Then I will call to see if they take reservations or at least allow names to be put on a list.
I will have checked the particulars of the expo and packet pick up (you are likely going to have to walk through the expo to get to packet pick up--they have learned from Disney) so I know when to get to packet pick up. Now I like to get this out of the way ASAP. In fact in Dallas for White Rock the packet pick up was a little ways away from my hotel which was near the start/finish. So when I landed, I got my rental car and went directly to packet pick up. Again, if there is an issue I want plenty of time to work it out.
I prefer not to spend a lot of time in the expo. The one exception might be a very interesting speaker, but honestly I follow running pretty closely and am not really an autograph seeker. So if you are traveling with a person who really likes expos, then you need to decide what you want to do. My default is that each person needs to decide what is best for him/her to prepare for a race.
For race day, I will tell folks my schedule and see who wants to tag along. I like to get to races earlier--I hate feeling rushed and want plenty of time to warm up, hit the porta-let, etc. So I will have figured out how long I think it will take me to get to the start and how much time I think I want for bag check (if I am checking one), porta-let and warm up (although for a marathon I do very little warming up).
The other question that comes up when traveling with a group is: do we run together. Typically when I would go to a race, I am going for the best performance possible so my default is to run my race. If a running partner and I have the same time goal that is great. In fact I really enjoyed running the first half of the Chicago Marathon with a training buddy until my hamstring decided to give out. We had agreed before hand that if one of us needs to drop back, the other will press on. We are not Special Forces: A man can be left behind!
I have friends who are marathon tourists: they run marathons for fun and often they will agree to run at the pace of the slowest person. Now for them that is fine since they all run about the same time anyway.
Talk with your folks about what to do if someone is feeling great or poorly so that if you drop back no one is feeling like they have to stay with you. Let's face it you likely running in a city or on a course where there are others.
Also plan for where to meet after the race and how long to meet. With cell phones this is much easier (if you take your phone and check it with your bag). The meeting spot could be back at the hotel. I would have everyone call and leave a voice mail once they were finished and/or back at the hotel. Or maybe everyone is going to meet right after the race some place close by the finish. Personally I am a fan of meeting back at the hotel. That way if someone finishes early then that person gets back to shower, grab a nap and do whatever each person needs.