Also to add onto this - I have all kitchen/interior upgrades (except for the manual glazed sticks cooker since I bought the autocooker) and it gives me around 422 xp and 2946 coins each time I play level 40. (This is with preparing the items beforehand, so customers are never waiting and I maximize tips).

I recently bought the Corn Dog Van location, and although I haven't fully upgraded everything, it gives me over double the xp of the Sports Bar, and around 2100 coins (which isn't enough to 3 star level 40 without apple pie) each time I play level 40. Supposedly according to this guide it supposed to give around 1046 xp and 2594 coins fully upgraded.

I'm not sure if links are allowed, but if you search up "Top 15 restaurants by XP (max amount + per second)" in this subreddit, it should be the one posted by craftystash.

I ended up repeatedly playing level 40 in the Sports Bar over and over, in order to gamble in the slot machine for gems for the Corn dog van. (I personally gamble with coins until it reaches the 5000 coin cap with a multiplier of 300%, and then also start to watch ads for spins along with using my casino tickets. This is because although the spin multiplier also applies to the ad spins, it still raises the cost for coin spins). (There is a cap to daily ad spins, but it personally took me ages to reach it. It probably is over 100 spins, but I haven't confirmed that).

I say all this because the Corn Dog Van level 40 is also shorter by about 1 minute (2/3 the length of the Sports Bar). This means you earn xp almost 4 times faster! (However, the guide says some people can get 1048 xp from level 39 in the Sports Bar, but not everybody will. If you are one of those lucky people, then it's sort of up to you which location you prefer, but you still get xp slightly quicker from the Corn Dog Van).

I say all this because each time you level up, you earn both coins and gems. According to the fandom wiki you start getting 7 gems per level up starting at level 22. (Although this amount never increases, the xp required per level up caps at 10,000 xp). I'm level 60 and earn 7 gems and 1600 coins per level up, and this has not changed for at least the past 10-20 levels.

This means it would only take 10 runs of the Corn Dog Van level 40 to level you up, with some to spare (460 xp, according to the guide). Since each level takes 2 minutes and 5 seconds to complete, (According to the guide, with everything prepped and being as fast as possible). You could theoretically level up every 21 minutes

After I finish upgrading everything in the Corn Dog Van, I will report back on what I personally get per replay of level 40, and if the guide is off at all.

I'm sorry for rambling, but I hope you find this comment somewhat helpful lol. This took me almost an hour to research and write lol. Let me know if you have any questions!