Is it grammatically correct to use もし and/or 〜ば form along with the 〜たい form to convey desire in a conditional clause?

Question

My impression when using conditionals, most of the time, you lose the ability to express desire. For example, when conjugating to -たら、you have to use the past tense of the verb. Is it grammatically correct to use もし or ば form to convey desire in conditional?

もし公園に行きたいんですが、電話して下さい。

or

公園に行きたければ、電話して下さい。

Answer 1

行きたければ is not past tense. It comes directly form 行きたい.

iku (行く) to go
iki-masu (行きます) to go
iki-tai (行きたい) want to go
iki-takereba (行きたければ) if you want to go

行きたい comes from 行きます by replacing "masu" with "tai".
行きたければ comes from 行きたい by replacing "i" with "kereba".

You can use もし to reinforce the conditional. The use of もし in this case is optional.

もし行きたければ
If you want to go.

There are other ways to express conditionals.
For example you can use なら:

もし公園に行きたいなら、電話して下さい。