It might turn out to be a rather thin coffee cake. Two bread loaf pans might be better.

A tube pan is designed to cook from the inside and the outside. Recipes for a tube pan don't necessarily work in a flat pan. Shielajoyce's suggestion of a loaf pan is good....or use your bundt pan....it won't hurt your pan.
Or make that old Merk's Coffee cake...turn it out of your pan, cut it in half, wrap well and freeze half.

http://www.cooks.com/recipe/qf9542h9/merks-coffee-cake.html

I may go with the Merks recipe then because the reason I am making the coffee cake is to use up some sour cream someone gave me, (plus I love sour cream cakes). I guess I could layer a struesel topping throughout a bundt cake too, but half a bundt cake frozen is awkward not only to store, but to serve later on unless you have enough guests to pre-cut all the slices! (I'm having the fondest memories of my mom having folks over for cake and coffee, and it being my job to carry all the china dessert plates with pieces of Sara Lee cake on them, out to the guest on a tray. Sad that people in general so seldom entertain that way, and me in particular! My set is either out sick or too busy/exhausted with work or family.)

A bundt pan i just a tube pan with a rounded bottom rather than flat. How is that difficult? I often make a cake of some sort and freeze half. I thaw the frozen half in the refrigerator and cut slices just as I did with the unfrozen half....or just as I would with the second half if I were serving the whole cake at a party.
Funny, Merk's coffee cake is called "Margaret's Coffee Cake" in my recipe file....because my mother had it at her friend, Margaret's house, got the recipe and passed it on to me!

I hate greasing pans, and my futzy bundt pan is the worst. And I rarely pre-cut cake slices to serve. So the idea of freezing and then thawing and having a half of a ring shaped cake is not appealing in any way to me and not worth the effort. YMMV. If I'm going for splash and dash at a big party I do on occasion make a bundt. But this is not one of those times. Even at birthday times, my family is so small and our dessert consumption so limited, I just make a round or square one-layer cake usually in a 8 or 9 inch pan. I'm amassing quite a collection of small cake recipes.

I bought both half size bundt and tube pans so that I can make two smaller cakes. Eat one now and give one away or freeze one.

Baking spray is amazing stuff...spritz and your pan is greased

Landfill issues with the baking spray. I'm going totally lazy and making cupcakes. Perfect for serving and freezing! I get recycled paper cups for them.

I made the cupcakes today. I didn't use a streusel filling/topping, just the sugar, cinnamon and walnut mix that the recipe called for. They came out ok. They look like mushrooms because I overfilled the cupcake tins. I tried to fill them half way, put in some of the sugar mix, and then fill the rest of the way and top with the sugar mix, and that ended up being kind of a waste of time and energy. They tend to come apart at the seams so if I ever make cupcakes out of this recipe again, I will just fill the cupcake tins 2/3 full and then top with the sugar mix. I got 14 cupcakes and I could have gotten 16-18. A little too sweet for my taste but that is probably due to my running out of sour cream and subbing half sweetened vanilla yogurt. I will make again, but probably just put in two round cake pans. That would have been fine.