Please, do also... or Please also

Solution 1:

Neither of your examples sound natural. Adding "do" before the verb sounds rather archaic and formal. Putting "also" before the verb makes it unclear what "also" modifies and splits the verb from "please", which sounds unnatural. If you mean "visit this house in addition to another one", I would say, "Please visit this house also." On the other hand, if you mean "visit this house in addition to doing another activity", I would say, "Also, please visit this house." Strictly speaking, however, either of these sentences would be correct in either situation (and the former sounds a little better).

The main problem with your original sentences (besides the "do") was splitting "please" and the verb.

Solution 2:

In the first instance, the presence of do makes for a strong suggestion that contradicts a common assumption. Please, do also visit this house would be in addition to doing something else that is not house visiting, such as filing application paperwork. I can imagine it in this context:

I would very much like to entertain your request for full membership in our fraternity. You must however fulfil certain requirements. First, file your papers in the main office. Then, knit fifteen colorful scarves. Leave these in the trees around the dean's house. Please, do also visit this house in the morning so that we might assess your courage.

In this case, you wouldn't expect that someone pranking the dean's house would then visit the house the following morning.

In the second case, it is simply doing something in addition to house visiting.

Come by the hospital around noon to pick up the roses. Choose your shoes from the shop around the corner. Please also visit this house on your way home.

Lastly, as Luke says, if you mean to express that there is an additional house to visit, you would normally say please visit this house also, rather than either of the choices you gave.