Look up used Parker 51 Pens on eBay. You will find a good one for around $120 or less, often a good one for writing will go for less because it has a scratch or dent. Just make sure it has an intact bladder and has been tested. A gnarly looking example in good working order will make a good story as well as be less attractive to criminals. I have one with no jewel and one with a broken clip and some with dents, but they are good to write with and they were available at a lower price.
I have several 51s and a Lamy 2000 and a Pelikan and some others, but the Parker 51s (in good working order) are by far the nicest to write with. And Parker in is also inexpensive. I like the Blue, not the dark Blue. I use the Lamy and Pelikan on sketching expeditions because they have larger ink capacity which makes them more useful to use for a larger sketch. But the Parker 51s are ideal for journalling.
Don't forget to pack some ink if you are taking a fountain pen on an extended adventure. A Nalgene Wide Mouth 50ml is useful to carry the ink, stored inside double ziplock bags. Or if you are not worried about the weight, just take the Parker Quink bottle inside double zip lock bags. I keep the box and keep the jar in the box when travelling. It is amazing how far a tiny spill of ink can get.
If you are going into a pressurised aircraft cabin, it may pay to buy a packet of 12 BIC finepoints or crystals and leave the fountain pen inside a plastic bag on the aeroplane. Although cheap and plentiful, BIC biros go back to 1945 and are still a nice biro to carry, with a nice history to study.
For a journal, the Moleskine type journal is good. I do not think there is such a thing as a "beginner" journal. You just need to work out what you like.
I make my own journals. It is not hard and you can make sure you have the best available paper for a low price. For an adventure I will break down a sheet of Arches 185GSM Smooth or Hot Press paper. It will make a 16 page single sided or 32 page double sided book about A5 size. Or a 32/64 page book about A6 size. There are videos to show you how to assemble and bind a book. If you already have some archival 90GSM copy paper, you can just fold the A4 in half to make pages for an A5 size journal.
At home I just use a four ring binder and a clip board. I carry loose leaf paper in the clip board and put it in the binder when its written on. The binder has TABs for months and my projects. I can buy high quality loose leaf paper in packets of 100 sheets for under $10. I can take it on a car based adventure, but its too hard for a bus or walking or riding a bicycle.
If you have not started journaling yet, start now, don't wait for the adventure to find out how you like to do it and to develop the necessary habits required to make it a success for you.