Both of these options are viable depending on what you want to do.
Creating an entity such as an LLC, LLP, LP, or S corporation can be a good idea for estate planning or tax purposes, depending on the value of the minerals. Talk to a CPA or tax attorney to get the specific benefits.
Entities cost money to form and have legal requirements to maintain, such as regular member meetings. You also have to file an entity tax return.
Depending upon what you are going for, a simple gift deed of an undivided portion of your minerals will give your child a share of the minerals, depending on the effective date of the deed. This will give your child the right to execute a lease and receive a share of the royalty.
You can also gift only a portion of the royalty or the right to lease bonus, and keep the executive rights, so that you will have sole control over leasing.
Basically, you have a ton of options. Depending upon what you want, each choice has different advantages and disadvantages.
Since you have interests in different states, a CPA for tax questions and a land professional for mineral management can probably provide the best guidance.