The Crusades cover a period of several generations, with death from travelling and disease before any battlefields were reached, as well as competing political/religious and international tensions means that the travelling was often all some participants managed to do. The first one in winter 1095 to the Holy Land succeeded in establishing 4 Crusader states, the fourth veered off to sack Constantinople from 1198, then there were 'side'/ unofficial crusades such as the Children's crusade of 1212 (which understandably for the time, was long on enthusiasm but painfully short on logistics), and the final eighth/ninth in 1270 only got as far as Tunis (french the eighth) before the king died so they all sailed home again, though the english (ninth) continued on. Tripoli fell in 1289 and Acre in 1291, though parts of the Ottoman empire that governed those areas did retain some continuity in the administration of organising christianity. So it covers the period from 1095 to 1291 as a minimum.

There are various 'eye witness' accounts written by actual participants in the Crusades, within their own lifetimes, at least to the best of modern knowledge they are such. Three of which I can recommend as interesting & enjoyable reads in themselves that may give you a decent start in your research, plus one outlier:

1. There's a book Gesta Francorum et aliorum Hierosolimitanorum (usually just called Gesta Francorum) on the First Crusade of 1095+ written within 10 years of the Crusade by an unknown author. This was a set text for History A Level 30 years ago, and I suspect it will contain the flavour of life you are looking for - I vividly remember being startled to read the passage about crusaders and their 'ladies' having their pubic and armpit hair removed (which challenged my ideas of how 'clean' or 'dirty' mediaeval people were).

It is not exactly an easy read (in the English) but it is entertaining in between the long lists of names of participants and repetitive actions attributed to each of them. The author is held to have been a knight, in the service of a greater lord, so it gives a view of what it was like to be there from the point of view of someone who had contact with those who made the decisions about what the armies would do from the perspective of someone who was going to be involved in the fighting - he started off in the service of Bohemond de Taranto, then Raymond of Toulouse. Unfortunately, it remains very expensive, well over a hundred pounds sterling even second hand, being something of a niche market, which is why I've not reread it since.

That said, the Gesta Francorum was, at the time, seen as being rather 'rustic' and not sufficiently 'ennobling' of the historic endeavour of the first crusade, so it was rewritten by several (relatively) contemporaries. One of which translated rewritings, by Guibert de Nogent, is available as a pdf online FOR FREE (which I'm quite excited about) - here - http://public-library.uk/ebooks/03/18.pdf . Unlike the author of Gesta Francorum, Guibert was a cleric and not an eye witness to the Crusade, and whilst I'm aware there are differences between the two, not having read one for 30 years and only just discovered the rewrite is available online so not having read it yet (though I plan to this week) I'm afraid I don't know if the details of daily life that made it interesting to me as a study text and memorable 30 years later, have been omitted as irrelevant by Guibert. However, given a choice of spending over a hundred pounds or downloading a free pdf, is probably worth a punt.

2&3) Another first person eye witness account (which I do own as it's a Penguin paperback you can get in the UK for under five pounds sterling) is Joinville & Villhardoin's Chronicles of the Crusades. Joinville's account covers the fourth crusade to Constantinople from 1199+ The saga of how a crusade against the muslims in the middle east ended up with the violent sack of a fellow christian city Constantinople is a gripping narrative overall, if somewhat bewildering to actually read and keep track of who is doing what where and when.

Villhardoin's is a Life of Saint Louis (the french king) a period of 50 years +/- from 1226, written to support a push for Louis' cannonisation. These don't have so much about the minutiae of personal lives in the same way as Gesta Francorum (no spa days there!), but are an interesting read nevertheless as they give an insight into how the mediaeval mind sees the world and their place in it and how they interacted with the people making the decisions about the wars waged.

Outlier - My final suggestion would be Geoffrey Chaucer's Canterbury Tales, which again is available in paperback, in modern english translation (Gesta Francorum was written in Latin, and Joinville & Villhardoin in 'old' French). Although it was written around a hundred years after the fall of the last crusader states, in 1392, and apart from being a really entertaining read, it does give vivid descriptions of what daily life was like for particular segments of society - the knight, the merchant, the widow etc. in Chaucer's time. Given the context of your fiction, any disparity between the actuality of daily life in say 1090 for the first crusade or 1390 for Chaucer's satire/comedy on stereotypical pilgrims of the age may not be fatal for your needs?

Finally - Where to find some context to help you understand who was doing what where and when? That I can't really help you with - back 30 odd years ago we used Steven Runciman's 3 volume History of the Crusades to give context and more understanding of all the various people and army movements being discussed in the eye witness accounts - though I understand that in the decades since, far better sources have been written, of which I know nothing and hopefully someone with more up to date knowledge will cover some of them.

In the meantime, I did find this list of sources where 34 mediaeval historians were asked for their top 10 books on the Crusades - https://apholt.com/2017/07/27/historians-rank-the-most-important-books-on-the-crusades/ - which you may find useful as it has annotations on why the books are important (for better or worse), and also covers the Crusades from the perspective of the Muslims.

PS I personally would read Gesta Francorum, Joinville & Villhardoin and Chaucer for pleasure which is why I have replied, in themselves they are really good reads.