first 5k on Saturday

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My plan is to walk (I don't run), but walk quickly. They only time the 5k up to an hour so I want to make sure I get done in under that. I do the elliptical 3x a week for 45-50 minutes and zumba once a week for an hour. Tonight I did 3.1 miles on the treadmill in 51 minutes. Its really hilly where I live so its not easy to get miles in outdoors. Luckily the course for Saturday is flat.
Anyway, so for the rest of the week I'll be working out on Tuesday (zumba) and Thursday (gym), Wednesday is typically my off day. Do you think I should get some miles in Wednesday and take of Friday or get in miles every day this week?