Anybody doing two-a-day workouts?

I've been doing that for about 3 years now.

As long as you're eating enough and taking recovery days each week, it can work really well.

Rowed this morning and heading out to my indoor cycling class in a few minutes, tomorrow I'll run before breakfast and do my weights after work.

I did find myself struggling with my run a bit last Saturday as I had a 70 minute weight session and a run a few hours later (I changed up my schedule to accommodate my daughter's 8:30AM soccer practice and going for a run with my son) Normally I run early in the morning and do my weights later and hadn't had any difficulties so far (I'm not lifting like a bodybuilder would though)

There are quite a few runners here on MFP who will do two runs a day depending on where they are in their training cycle.

How long have you been running for? Weekly mileage? Do you have any specific goals?

Congratulations on hitting 5 miles, that's a real landmark in any runner's career.

Based on being a runner for less than a year I'd be fairly conservative in my approach (I'm an old geezer - running conservatively has kept m relatively injury free) and your goal of just finishing is the right one! If you have the time you could do running and core on the same day (check out runnerwsworld.com - http://www.runnersworld.com/training/workouts - for ideas) but I'd probably keep strength on a separate day for now just to give you more recovery time between workouts. As you're training for an endurance event most of your strength training will relate to addressing muscular imbalances (particularly glues & hips) and injury resistance so the sessions won't be hugely time consuming and twice a week should suffice.

Listen to your body, keep things in balance and have fun. (There are some running groups here at MFP you may want to join to share training ideas etc - we have some very experienced and talented runners here)