I prefer a lens that is wider than normal for 4X5. I chose 135mm Fuji and have not regretted it, it serves most of my purposes. My next lens was 240mm G-Claron and that too was a wonderful choice for a long(ish) lens. My Tachahara will not support anything over 300mm so I'm about maxed out in that direction. I would like a 90 as a wide angle lens but my experiences with Landscape photography does not suggest I have really missed anything.
To go wider than 90mm may entail recessed boards which present issues with cable releases, setting shutter and speed controls.
I wasted time and money with a cluncker camera thinking I could learn some basics to decide if a "real" camera was going to work. The learning curve of a properly working camera is much quicker than trying to work around mechanical problems, and if you are interested in getting your feet wet with 4x5 you will be hooked and might as well not to have upgrade in the first year. Toyo makes good cameras,
Good luck, and welcome to APUG; there are a lot of people here willing to share their experiences.
It might be worth hooking up with a local LF user and trying a few lenses before dropping another wad of cash - If you were close by, I'd have said pop in for a coffee & natter.
P.S. I'd suggest avoiding the Xenar lenses - Whilst often found cheap, I've never been impressed by the coverage and nearly always hit the limits on the ones I've tried.
I'm 56 and that's not on the timeline yet.
To the OP, I love my Fuji 150 6.3, been shooting with it for 30 years. Just got a Fuji 135 5.6 and it's OK but I'll need to get a little more comfortable with it.
I would recommend a 135 to 150 lens paired with a 210 to 240 and get use to those lens. Buy quality.
tim in san jose
Strangely I had my 210mm Symmar for some time (3 or 4 years) before I really started to use it and I've used my 300mm twice in over 20 years (but I can use it on my 10x8 cameras as well). I guess I needed to learn to see with the 210 and had just become too used to shooting with a 150mm or wider. I tend to shoot subconsciously, by that I mean I instinctively position the tripod (unless working hand-held) and know what lens to use having already decided on the framing of the image.
if you can't decide between 2 focal lengths, you might consider
getting a convertible lens so you have 2 focal lengths instead of 1.
i believe there is a schneider symmar convertible that is both 150 and 210
it is the age-old plasmat design ( like a g claron ), so both focal lengths are quite sharp stopped down.
I would choose a 210mm unless I needed something wider. However, I don't shoot many landscapes with 4x5.
In 35mm format, I was shooting 99% of my landscape pictures with 50mm lens. After switching to 4x5, I use 180mm for it. Many people here suggest 150mm, but I found it a little bit too wide in most of situations. It's up to your personal feeling. Also the coverage should be considered and usually 180's have it bigger.
My kit contains 65, 90, 135, 150, 180, 240 & 350 lenses. That being said, my favorite is the tiny and outrageously sharp 135mm 5.6 Apo-Sironar, wow, what a lens with nice coverage!
The 90 6.8 is fab as a wide and sees a lot more use than my rarely used but still useful 65 Grandagon. The 150, 180 and 350 Schnieder Apo's all use 58mm filters so that is nice.
And then of course is the fantastic little Fuji 240 F/9 A.
I find that unlike 35mm or even 120, I need more lenses in the field with the 4x5 because it is 100% tripod mounted, so I usually opt for all of them on road trips and 5 of them when hiking.
But seriously, pick up a clean used 135 Apo-Sironar and you are set, brilliant lens!