Training for a 10K

There may be a new 10K OWS in my area next year and it's a swim I'd like to do if it actually materializes. However, I need to train for that. THe longest open water swim I have done is a 2 mile cable swim this past August. I've since swum 2.5 miles in a pool. (mentally boring but a good mental training for that very reason). I'm also planning on a 5K swim next spring as the next step in increasing how far I am going to swim in open water. Come next spring, I can do longer swims in the Hudson with my husband accompanying me on his paddleboard. I haven't done that yet because I just learned about place where one can do that. Now that it is getting colder, I am restricted to the pool. Any suggestions how one can train for a 10K in a pool and then what is recommended in open water once it is warm enough again? Any advice on feeds in a 10K would be great too. I can swim 45 minutes before I start bonking unless I've had a Hammer gel before a workout (then I'm good for longer than that.) Thanks all for any tips, advice or other words of wisdom! :)