Are these goals in priority order? If so, my recommendation would be to find a 5k in early summer to train for and postpone the half marathon goal until fall. The 5k training will give your body a bit of a break from the endurance running and give you a chance to work on speed. It could be enough change to spark up some more motivation as well.
I realize you have a busy schedule so maybe a fall half isn't feasible, but if that's the case focus on the half goal first and then find a 5k for the fall. My point is, pick one race distance to go after and then switch. I used to think training for anything less than a half was for new runners but that's a totally wrong assumption that I had. It's actually incredibly beneficial to vary the training focus throughout the year.
They're not in priority order. I am going to attempt to differentiate my training cycles, so that's a good point you made. But considering the timing of things, it's going to be easier for me to find an early summer half (such as the June 18th one) and a late summer/fall 5k. Fall is such a crazy time of year for us. We had 7 weekend meets we traveled to last year in September and October. It might actually be a little easier this coming year since we won't have 3 separate XC schedules plus weekend soccer (and 2 week-night practices). I'll
only have the HS and elem XC schedules, plus soccer. I'm hopeful that they are able to publish our varsity XC schedule by April or May so I can see what weekends I'll need to block off for that and then possibly reassess my plan. And if not, 5ks are pretty easy to find. I could even be the embarrassing mom and run in the open race at one of their XC meets
A fall race will more than likely *have* to be on a Sunday (for a half) and unfortunately that eliminates about 80% of them, and it seems like (but may not actually be factual) more of the Sunday races are trail races. There are so many 5ks that finding one to plug in where possible shouldn't be too much of a chore.
I feel like I'm going to give myself a pretty decent break from a significant amount of running right now...for about 2.5 months where I'm running <15mi/wk, and then slip back into half training for that June race. And after that I'll probably switch to 5k training because it'll be SUMMER and SUN and all things HOT and 5k training doesn't necessarily take as much time as half training.
Plus I'm not a huge fan of speedwork. Because it's hard, and I feel like it highlights how not-fast I am.
AND, if I do a half training cycle, a 5k training cycle, and THEN if I can talk DH into going back for MW in January I will be able to fit in an 18wk training cycle for that.