So, when you say "i'd like to..." use "gostaria de + infinitive" once it is futuro do pretérito, not subjuntive. Maybe you wont have the opportunity to make your wish come true. Then, we have "eu gostaria de pensar no/sobre seu caso"

Pensasse is also 3rd singular in subjuntive ( -que- ele/ela/você pensasse).... everytime you use "I/we would like you to..." you must use subjuntive, since it shows a desire, feeling,... "gostaríamos que você aceitasse nossa proposta..." -- this desire takes a future action: "quero que fale com ela" = "i want you to talk to her" (later...) you'll probably see QUE ("that") somewhere in the sentence.....