Hey,

I am baking my dad's 65th Birthday Cake for his party on Sunday. This was my plan although I am now in doubt. (Using the same weight for all ingredients Vic sponge)

Thursday Evening - Bake the cake, allow time to cool, cover in buttercream

Saturday Morning/Afternoon - cover in fondant (ready to roll icing) and decorate

Sunday - Eat cake

Is the above timeline doable or am I being too unrealistic with baking/decorating time to eating day? Any advice would he greatly appreciated. I really only have tomorrow and Saturday morning/Afternoon to prepare

That should totally be doable. 

You schedule sounds fine.  Unless you have awfully elaborate decorations, this schedule should be stress free.