It's hard to find a machine that will do everything well. Usually there is a compromise there somewhere. If you're hunting salt water or salt wet sand, you'll need something to handle that environment. If that area is reletively trash free, a PI type detector works very well but it will pick up every bobby pin, nail, paperclip, and all other iron junk. If you need discrimination, a multifrequency machine like what Minelab makes it a better choice. A Sovereign, Explorer, and E-trac will all work great if you don't venture beyond knee deep, For deeper water, the Excalibur and CTX3030 will shine. The Excalibur can go down to 200 feet and the CTX, 10 feet. Of the previous choices, The CTX, E-trac, Explorer, and Sovereign will all work good in a park setting too. The Excalibur, not so much as there is no depth meter, limited tone I.D., and no target I.D. Most Pi detectors don't have those features either but you'll have to investigate each model to verify. All of them will find large gold. The smaller the coil and higher the operating frequency, the better it will be at finding small gold. Tiny link type chains are hard for almost every detector except gold machines which are specialized to find small gold. The gold machines are not the best choice for parks but they don't do too bad at the beach....as long as you don't need discrimination. As for the rules, look up the ordinances yourself for that particular patch of ground. If it's public, the rules will be posted somewhere.....either online or at the appropriate government office. Just don't ask any of the bureaucrats you run across, They have no interest in helping you in your hobby and usually just say it not allowed so they're not on the hook for "giving permission". Joining a local detecting club can better help in getting your questions answered in that respect. Sometimes, you may think it's not allowed when in reality, nobody cares one way or the other. If you start asking people permission, it just brings attention to what you're doing which is the last thing you want the government to know. Now if it's private land, you definitely need to get permission from whoever is in charge of that piece of land whether it be the owner, a renter, manager, worker, etc. Someone to take the heat if someone higher up gets their panties in a wad. If you use good recovery practices, you shouldn't have a problem.
