My colleagues and I taught elections and government for several years using the Candy Bar Election theme. We had the unit down to a science when I had to leave fourth grade for another position. We learned the entire election process from choosing the Candy-Dates (candidates) to, campaign ads, to debates, to voting day! What a sweet time of learning! Thanks Sherry, Julie, Traci, Pam, Sarah, Heather, and Stephany for making that unit one I will never forget!
Here are some links to resources online for schools that have done similar things:
Consider using Poll Everywhere to make your mock election more digital.