"Mimi ninapenda kusafiri Kenya na Tanzania. Ninataka kuona Nairobi, Mombasa, na Dar es Salaam. Pia kusoma Kiswahili.
Sitaka kusoma nje ya nchi, ninataka kufanya kazi ama kujitolea nje ya nchi.
"Mimi ninapenda kusafiri Kenya na Tanzania."
Hongera Joe! Umeandika vizuri!
However, I think you should use 'nge' (would) in that context instead 'na'. You can use 'na' (which is used talk about habitual and on-going activities) if you often travel to Tanzania and Kenya (ninapenda).
Personally, I would use 'nge': to sound like I'm expressing a wish.
Ningependa = I would like (because you have never been to Tanzania and Kenya but you would like to visit the countries).
If traveling to Tanzania and Kenya is something that you usually do and/or like to do, then 'ninapenda' is just fine. You can drop that 'mimi'. Most native speakers, especially Tanzanians, don't start their sentences with pronouns cuz the verb tell it all.
"Ninataka kuona Nairobi, Mombasa, na Dar es salaam."
I feel like something is missing in the verb 'kuona'. Nairobi, Mombasa, and Dar es salaam are objects in the sentence. There should be something in the verb representing them (just the first city), and that is 'i'.
I would say nataka (nitataka also sounds perfect – it sounds like you will want to visit/see Nairobi and Mombasa when you get to/are in Kenya, and Dar es salaam when you get to/are in Tanzania) kuiona............ (Nataka/nitataka kuiona Nairobi, Mombasa na Dar es salaam na kusoma Kiswahili pia.). I wouldn't put a period after Dar es salaam. I would just use 'na' (and) join the two sentences.
"Sitaka kusoma nje ya nchi."
In simple present and present progressive tenses, the verbs with negation (not/never in a sentense) end in 'i'. For example, sitaki, hatutaki, hautaki, hamtaki....... Say "sitaki kusoma nje ya nchi".
"ninataka kufanya kazi ama kujitolea nje ya nchi. Siku moja!" is correct. I would say "ningependa kufanya kazi ama (au) kujitolea nje ya nchi siku moja!".